High-grade interval in NW25-57 of 117.0 metres at 1.50 g/t Au Eq., including 52.5 metres at 1.91 g/t Au Eq.

Highlights:

• Selected gold-equivalent assay intercepts include:
  • NW25-57: 117.0 metres at 1.50 g/t Au Eq. from 231.0 metres, including 52.5 metres at 1.91 g/t Au Eq. from 256.5 metres
  • NW25-54: 75.0 metres at 1.37 g/t Au Eq. from 246.0 metres, including 42.0 metres at 1.69 g/t Au Eq. from 279.0 metres and a higher-grade interval of 18.2 metres at 2.86 g/t Au Eq. from 333.7 metres
  • NW25-53: 107.7 metres at 1.20 g/t Au Eq. from 254.0 metres, including 67.5 metres at 1.76 g/t Au Eq. from 254.0 metres
• Mineralization at Northwest Expo has now been extended to approximately 1.1km of strike length
• Results confirm consistent mineralization, and higher grades in Northwest Sector of pit shell
  • Northwest Sector: significantly higher-grade mineralization discovered within resource pit shell
  • Central Sector: high-grade mineralization from PEA resource model confirmed
  • Southeast Sector: shallow mineralization from PEA resource model confirmed
  • Deep Sector: lower-grade mineralization from PEA resource model confirmed
• PFS infill drilling campaign finalized, with 13,980 metres in total and results from Red Dog expected in Q2 2026

VANCOUVER, British Columbia--(BUSINESS WIRE)--Mar. 31, 2026-- Northisle Copper and Gold Inc. (TSX-V: NCX, OTCQX: NTCPF) (“Northisle” or the “Company”) is pleased to announce additional drill results from its infill drilling campaign at the Northwest Expo deposit. A total of 8,464 metres were drilled at Northwest Expo with the objective of upgrading Inferred resources to the Indicated category in support of the ongoing Pre-Feasibility Study at the North Island Project (the “North Island PFS”), while improving confidence in the continuity and geometry of higher-grade mineralization at Northwest Expo and extending the strike length of the mineralized footprint.

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Figure 1: North Island Project Showing Location of Deposits and Prospects

Sam Lee, President & CEO commented “We are highly encouraged by these results at Northwest Expo, which expand our understanding of the North Island Project’s broader exploration potential. The results have increased our confidence level in the first phase of the project by identifying higher-grade, gold-rich mineralization in certain zones within the 2025 PEA pit shell. With a robust balance sheet, Northisle is uniquely positioned to simultaneously create value through project development and drive continued growth in the mineral potential of the district.”

Discussion of Drill Results

The 2025 infill drilling program at Northwest Expo was designed to improve confidence in the continuity and geometry of higher-grade mineralization while supporting the conversion of Inferred resources to the Indicated category. A total of 8,464 metres were drilled, with hole distribution designed to confirm the continuity of mineralization and the distribution of gold and copper grades. Results received to date demonstrate consistent mineralization over broad intervals, with locally developed higher-grade domains that contribute to the gold-rich profile of the mineralized system at Northwest Expo.

The results confirm that mineralization at Northwest Expo is characterized by continuous, near-surface to moderately deep intervals of gold-rich copper mineralization, with molybdenum contributing significantly in some instances to the overall metal endowment. The current results highlight both the lateral and vertical continuity of mineralization, as well as the presence of discrete higher-grade zones within broader mineralized envelopes.

Holes NW25-42, NW25-43, NW25-44, NW25-45, NW25-46, NW25-47, NW25-49 and NW25-51 were drilled in the southeastern portion of the deposit, targeting the extension of mineralization beyond the limits of historical drilling used in the current resource model. Results from this sector confirm the continuation of mineralization, with broad intervals such as NW25-45 (99.0 metres at 0.43 g/t Au Eq. from 56.0 metres) and NW25-46 (102.0 metres at 0.55 g/t Au Eq. from 348.0 metres) demonstrating consistent grade over significant thicknesses. In addition, higher-grade intervals within these broader zones, including NW25-47 (51.9 metres at 0.77 g/t Au Eq. from 349.4 metres), support the presence of internally developed higher-grade domains (see Table 1).

In contrast, holes NW25-53, NW25-56, NW25-57, NW25-61 and NW25-63 were designed to test the northwestern extent of the resource model and returned intervals characterized by significant thicknesses and higher gold grades, demonstrating continuity of mineralization and supporting the potential extension of higher-grade domains in this direction. Notable intercepts include NW25-57 (117.0 metres at 1.50 g/t Au Eq. from 231.0 metres, including 52.5 metres at 1.91 g/t Au Eq. from 256.5 metres), NW25-53 (107.7 metres at 1.20 g/t Au Eq. from 254.0 metres, including 67.5 metres at 1.76 g/t Au Eq. from 254.0 metres), and NW25-61 (101.7 metres at 1.18 g/t Au Eq. from 242.7 metres, including 60.0 metres at 1.56 g/t Au Eq. from 258.0 metres), as well as higher-grade intervals in NW25-63 (10.2 metres at 2.25 g/t Au Eq. from 296.8 metres). This area demonstrates potential for continued growth, supported by consistently elevated gold grades and the persistence of mineralized intervals (see Table 3).

Holes NW25-52, NW25-54, NW25-55, NW25-58 and NW25-60 were drilled in the central portion of the deposit, targeting the core of the mineralized system and areas of previously identified higher-grade gold mineralization. NW25-54, which intersected 75.0 metres at 1.37 g/t Au Eq. from 246.0 metres, including 42.0 metres at 1.69 g/t Au Eq. from 279.0 metres and a higher-grade interval of 18.2 metres at 2.86 g/t Au Eq. from 333.7 metres, confirms the presence of high-grade gold mineralization previously identified in hole NW24-29 (see news release dated November 5, 2024), which reported 132.8 metres at 1.49 g/t Au Eq. NW25-54 is located approximately 100 metres above NW24-29 in the same section, indicating the presence of shallower higher-grade gold mineralization in this area.

Additional drilling in the central portion of the deposit confirmed strong continuity of higher-grade mineralization. NW25-60, which intersected 88.8 metres at 1.38 g/t Au Eq. from 198.0 metres, including 42.0 metres at 1.84 g/t Au Eq. from 240.0 metres, is located approximately 65 metres southeast of NW25-54 and approximately 60 metres south of NW24-29, and indicates continuity of the higher-grade gold mineralization observed in this area. In addition, NW25-52, which intersected 115.6 metres at 1.22 g/t Au Eq. from 248.9 metres, including 33.0 metres at 1.94 g/t Au Eq. from 269.0 metres, together with NW25-58, which intersected 61.2 metres at 1.15 g/t Au Eq. from 189.0 metres, including 17.3 metres at 1.81 g/t Au Eq. from 195.8 metres, and NW25-55, which returned 81.2 metres at 1.09 g/t Au Eq. from 287.8 metres, including 18.0 metres at 1.89 g/t Au Eq. from 291.0 metres, confirm the persistence and lateral continuity of higher-grade gold mineralization across the central portion of the deposit (see Table 2).

Holes NW25-48, NW25-50, NW25-59 and NW25-62 were drilled to test the depth extension of the mineralized system near the lower limits of the current resource model. Results from this sector confirm the presence of gold mineralization at depth, although at lower grades relative to other areas of the deposit. Notable intercepts include NW25-62 (159.0 metres at 0.51 g/t Au Eq. from 255.0 metres, including 54.0 metres at 0.79 g/t Au Eq. from 357.0 metres) and NW25-59 (43.0 metres at 0.29 g/t Au Eq. from 332.0 metres). Holes NW25-48 (27.0 metres at 0.31 g/t Au Eq. from 159.0 metres) and NW25-50 (30.5 metres at 0.26 g/t Au Eq. from 170.5 metres) did not intersect mineralization at the targeted depth; however, these results confirmed the presence of shallower, lower-grade mineralization consistent with previous Northisle drilling and historic results (see Table 4).

Additional to the gold-copper mineralization, the overall outcomes highlight the presence of higher-grade molybdenum zones spatially associated with the gold-copper mineralization, suggesting potential metal zonation within the system. This pattern may reflect a transition where gold and copper grades decrease while molybdenum becomes relatively enriched. Further analysis is planned to better define the spatial distribution of metals across the deposit and to evaluate the implications of this zonation on the geological model.

These results demonstrate the presence of coherent gold-rich, higher-grade domains within the deposit that remain open and locally enhance the overall grade profile. The consistent occurrence of internal higher-grade intervals supports the interpretation of lateral and internal continuity and improves confidence in the definition of higher-grade domains. The Company is planning follow-up drilling to further define and test the extent of these higher-grade gold zones.

Overall, drilling completed to date supports the interpretation of Northwest Expo as a continuous, gold-enriched porphyry system with broad higher-grade domains. Infill drilling is improving confidence in both grade continuity and geological controls, and ongoing and future drilling is expected to further refine the geometry of these domains for incorporation into future resource updates. To date, mineralization has been outlined over more than 1,060 metres of strike and extends from approximately 100 metres to 430 metres below surface, and remains open at depth and along strike.

Note on equivalent calculation for Northwest Expo:

Gold equivalent grade is determined by calculating total contained metal value/tonne, adjusted for recoveries, if known, dividing by the gold price, and then multiplying the resultant number of troy ounces of gold by 31.103. Copper equivalent grade is determined by calculating total contained metal value per tonne, adjusted for recoveries, if known, dividing by the copper price, and then dividing the resultant number of pounds of copper by 2,204.6. Analyzed metal equivalent calculations are reported for illustrative purposes and consider 91% recovery for gold, 73% recovery for copper, and assume 80% recoveries for Molybdenum and Rhenium as metallurgical testing has not yet been completed for these two elements on material from the Northwest Expo deposit.

Gold and copper equivalent calculations based on the following metal prices, which were used in the Company’s 2025 Preliminary Economic Assessment for the North Island Project: Au = US$2,150/oz, Cu = US$4.20/lb, Mo = US$21/lb, Re = US$1,950/kg. Intervals were selected based on continuous intercepts with Au grade above 0.1g/t Au or Cu grade above 0.1% Cu. Totals may not add due to rounding.

Intervals are drill intersections and not necessarily true widths. True widths cannot be provided at this time due to the uncertainty in the geometry of the mineralization. Drill intersections have been selected and composites calculated independently by Northisle. The locations and distances highlighted on all maps in this news release are approximate.

Figure 1 shows a map of the overall North Island Project including existing deposits, key prospects, and the focus area of this release.

Figure 2 shows the location of the drill holes announced in this press release in context with previous drilling in the Northwest Expo area, while Figure 3 presents a long-section highlighting results from this release, illustrating the distribution of drilling and mineralized intervals along the deposit.

Exploration and Development Milestones

Key project milestones for 2026 include the following:

• COMPLETED – Updated Preliminary Economic Assessment on North Island Project
• COMPLETED – C$39.5 million financing
• COMPLETED –BC Hydro Conceptual Review of Interconnection
• COMPLETED – Team additions and enhancements to support growth
• COMPLETED – Commencement of expanded baseline study program to support EA Readiness
• COMPLETED – Largest ever field program at North Island Project with 20,297 metres and 58 holes drilled
• COMPLETED – Confirmed mineralization at West Goodspeed over 1.2km strike
• COMPLETED – Identified copper-gold mineralization at the Cougar Target
• COMPLETED – C$115 million financing to advance the North Island Project
• COMPLETED – Infill drilling results at Northwest Expo, extending strike and highlighting higher-grade zones
• Q2 2026 – Infill drilling results (5,516 metres in total) at Red Dog (pending assay results)
• Q2 2026 – Initial metallurgicaltest results for the North Island PFS
• Q2 2026 – Integrated resource update for the North Island Project
• Q2 2026 – Commence extension drilling in Northwest Corridor
• Q3 2026 – Target for initiation of early engagement on mine waste storage area
• Q3 2026 – Initiate drilling at regional exploration targets
• Q4 2026 – Results from drilling at regional exploration targets
• Q4 2026 – North Island PFS results announced
• H2 2026 – Initial Project Description filed
• H2 2026 – Commence BC Hydro System Impact Study
• Ongoing –Continued positive engagement with indigenous rightsholders and local stakeholders
• Ongoing – Additional team additions to support further growth

Northisle Retains Renmark Financial Communications

Northisle also announces that it has retained Renmark Financial Communications Inc. (“Renmark”) to provide investor relations services to the Company (the “Services”). In consideration for the Services, Renmark shall be paid up to C$9,000 per month, starting April 1, 2026. The Services have an initial term of seven months ending October 31, 2026. Renmark does not have any direct or indirect interest in the Company, or its securities, nor any right or intent to acquire such an interest.

Additional Technical Details

Logging, Sampling and Assaying Procedures and QA/QC

The diamond drill core logging and sampling program was carried out under a rigorous quality assurance / quality control (QA/QC) program. Drill intersections in this release are typically HQ to 150 metres and NQ thereafter to the end of holes. After drilling, core was logged for geology, structure, and geotechnical characteristics utilizing MX Deposit —core logging software, then marked for sampling and photographed on site. The cores for analyses were marked for sampling based on geological intervals with individual samples of 3-metre length or less. Drill core was cut lengthwise in half with a core saw. Half-core was sent for assays reported in this news release.

A minimum of +9.9% assay standards or blanks and +4.7% core duplicates are included in the sample stream as a quality control measure and are reviewed after analyses are received. Standards and Pulps Blanks were obtained from CDN Resource Laboratories, Langley, British Columbia. Coarse Blanks were obtained from unmineralized course bagged limestone landscaping rock. Standards and blanks in 2025 drill results to date have been approved as acceptable. Duplicate samples sourced from both pulp and coarse rejects as well as quarter-core field duplicates add to the long-term estimates of precision for assay data on the project and precision for drill results reported is deemed to be within acceptable levels.

Samples were sent to the MSALABS in Langley, British Columbia, where the samples were dried, then crushed, split and a 250-gram (g) split was pulverized to 85% passing -200 mesh (-75 micrometres (µm)) size pulps. Clean crush material was passed through the crusher, and clean silica was pulverized between each sample. The pulps were analyzed for gold by fire assay fusion of 50 g of the 250 g split. Total gold content was determined by digesting the silver doré bead from the fusion and then analysing by AA (MSA Code FAS-121). All samples were also analyzed for multiple elements by taking a 0.25 g of the 250 g split which was heated in HNO3, HClO4 and HF to fuming and taken to dryness. The residue was dissolved in HCl and then analyzed utilizing ICP-MS (MSA Code IMS-230). Any copper analysis exceeding 1% had the pulp re-analyzed using the “Ore grade” ICP-ES finish to constrain copper content up to 40% (MSA Code ICF-6Cu). Any sulphur analysis from this latter analysis with a value greater than 10% was reanalyzed utilizing a Leco sulfur analyzer. Iron and Tungsten accelerators are added to the sample and a stream of oxygen is passed over the sample in the induction furnace. As the sample is heated, sulfur dioxide released from the sample is measured by an IR detection system and the Total Sulphur content is determined. (MSA Code SPM-210). MSALABS (Langley) is an independent, international ISO/IEC 17025:2005 accredited laboratory.

Pulps and rejects of holes with significant assay intervals are stored at West Coast Mineral Storage. The remaining split core is indexed and stored at the Company’s logging and office facility in Port Hardy, BC.

Drill Results in this news release are length weighted averages.

Qualified Persons and Data Verification

Dr. Pablo Mejia Herrera, P.Geo., Vice President Exploration of Northisle, and a Qualified Person as defined by National Instrument 43-101 Standards of Disclosure for Mineral Projects, has reviewed and approved the scientific and technical disclosure contained in this news release. Dr. Mejia Herrera has verified the data disclosed, including the sampling, analytical and test data underlying the disclosure, through multiple visits to drill sites, oversight of sample preparation protocols, and review of the QA/QC procedures applied to analytical results received from MSALABS.

About Northisle

Northisle Copper and Gold Inc. is a Vancouver-based company whose vision is to become Canada’s leading sustainable mineral resource company for the future. Northisle, through its 100% owned subsidiary North Island Mining Corp., owns the North Island Project, which is one of the most promising copper and gold porphyry projects in Canada. The North Island Project is located near Port Hardy, British Columbia on a more than 34,000-hectare block of mineral titles 100% owned by Northisle on a belt stretching 50 kilometres northwest from the now closed Island Copper Mine operated by BHP Billiton. Since 2021, the Company has discovered two significant deposits, expanded resources, demonstrated the economic potential of the project, and is now focused on the development of this compelling project while exploring within this highly prospective land package.

Northisle respectfully acknowledges that our North Island Project is located within the territories of Quatsino First Nation, Kwakiutl First Nation, and Tlatlasikwala First Nation. We are committed to collaborating with First Nations to build authentic, mutually beneficial relationships.

For more information on Northisle please visit the Company’s website at www.northisle.ca.

About Renmark Financial Communications Inc.

Founded in 1999, Renmark is a privately held full-service investor relations firm, located in Atlanta, New York, Toronto, and Montreal. For the past 25 years, Renmark has provided services in investor relations, media relations, and web development representing small, medium and large cap public companies listed on all major North American exchanges. With the largest roadshow footprint in North America, Renmark hosts a multitude of live streaming Virtual Non-Deal Roadshows across North America and Europe.

Cautionary Statements regarding Forward-Looking Information

Certain information in this news release constitutes forward-looking statements under applicable securities law. Any statements that are contained in this news release that are not statements of historical fact may be deemed to be forward-looking statements. Forward-looking statements are often identified by terms such as “may”, “should”, “anticipate”, “expect”, “intend” and similar expressions. Forward-looking statements in this news release include, but are not limited to: plans and expectations regarding the 2026 exploration program; plans and expectations regarding future project development; timing of key catalysts; planned activities, including further drilling, at the North Island Project; anticipated timing for drilling results from Red Dog; the Company’s anticipated exploration activities; the Company’s planned team additions or enhancements; and the Company’s plans for advancement of the North Island Project. Forward-looking statements necessarily involve known and unknown risks, including, without limitation, the Company’s ability to implement its business strategies; risks associated with mineral exploration and production; risks associated with general economic conditions; adverse industry events; stakeholder engagement; marketing and transportation costs; loss of markets; volatility of commodity prices; inability to access sufficient capital from internal and external sources, and/or inability to access sufficient capital on favourable terms; industry and government regulation; changes in legislation, income tax and regulatory matters; competition; currency and interest rate fluctuations; and other risks. Readers are cautioned that the foregoing list is not exhaustive.

Readers are further cautioned not to place undue reliance on forward-looking statements as there can be no assurance that the plans, intentions, or expectations upon which they are placed will occur. Such information, although considered reasonable by management at the time of preparation, may prove to be incorrect and actual results may differ materially from those anticipated. Forward-looking statements contained in this news release are expressly qualified by this cautionary statement.

The forward-looking statements contained in this news release represent the expectations of management of Northisle as of the date of this news release, and, accordingly, are subject to change after such date. Northisle does not undertake any obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as expressly required by applicable securities law.

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this news release.

View source version on businesswire.com: https://www.businesswire.com/news/home/20260331058559/en/

On behalf of Northisle Copper and Gold Inc.

Nicholas Van Dyk, CFA
Chief Financial Officer
Tel: (604) 335-3590
Email: info@northisle.ca
www.northisle.ca

Source: Northisle Copper and Gold Inc.