Mr. Philip Williams reports

ISOENERGY CONFIRMS HIGH GRADE URANIUM MINERALIZATION ON THE HURRICANE SOUTH TREND, WITH UP TO 4.21% U3O8 OVER 3.5 M, INCLUDING UP TO 11.6% U3O8 OVER 1.0 M

IsoEnergy Ltd. has released assay results from its recently completed 2026 winter exploration drilling program at the Larocque East project, home to the high-grade Hurricane deposit, in the eastern Athabasca basin in Canada. The results include high-grade uranium mineralization intersected within the newly reinterpreted fault zone along the Hurricane South trend, highlighting the potential to expand mineralization beyond the current resource footprint.

Hurricane hosts a current mineral resource of 48.6 million pounds U3O8 (triuranium octoxide) at 34.5 per cent U3O8 indicated and 2.7 million pounds U3O8 at 2.2 per cent U3O8 inferred (see "Qualified person statement" below). The project benefits from excellent infrastructure, located approximately 40 kilometres northwest of the McClean Lake mill, and features relatively shallow mineralization at approximately 325 metres depth, supporting efficient exploration and future development optionality. The deposit is located on the Larocque trend, an important regional structure that also hosts other notable high-grade occurrences, including those on Cameco and Orano's Dawn Lake joint venture.

Highlights:

• High-grade assays returned from hole LE26-248: 4.21 per cent U3O8 over 3.5 metres, including 11.61 per cent U3O8 over 1.0 metre;
• Additional notable intercepts include 2.75 per cent U3O8 over 0.5 metre in LE26-234 and 1.75 per cent U3O8 over 0.5 m in LE26-243 on the Hurricane South trend;
• Assay results confirm previously reported radioactivity (see news release dated April 7, 2026 ), validating uranium mineralization along the Hurricane South trend, and continue to demonstrate strong potential for expansion beyond the current resource footprint;
• Follow-up summer drill program planned with approximately 8,000 metres across 20 holes, focused on targeting the highly prospective Hurricane South trend.

Dan Brisbin, vice-president of exploration, stated: "The LE26-248 intersection is important as it is located along the southernmost known fault strands within the Hurricane fault zone, where drill hole density is lower than on faults to the north that host the high-grade Hurricane uranium mineralization. This intersection, along with mineralization intersected in stepout holes to the east like LE26-243 and LE26-234, highlights the potential along the Hurricane South trend. We look forward to further testing this mineralized trend in the summer and our project team is well advanced in program planning."

Operational update regarding Northern Saskatchewan flooding

IsoEnergy's operations at the Larocque East Project are not currently impacted by the continuing flooding in Northern Saskatchewan. The company is monitoring the situation closely. IsoEnergy's thoughts are with the communities affected across the region.

Qualified person statement

The scientific and technical information contained in this news release was reviewed and approved by Dr. Dan Brisbin, PGeo, IsoEnergy's vice-president, exploration, who is a qualified person (as defined in National Instrument 43-101, Standards of Disclosure for Mineral Projects). See the April 6, 2026, press release for information on quality assurance/quality control procedures as well as the complete exploration results from the previous programs disclosed herein. Dr. Brisbin has verified the data disclosed herein. Data verification procedures included comparing radioactivity measured on core with the RS-125 spectrometer with radioactivity measured downhole with the 2PGA probe, comparing RS-125 data with count-per-second values marked on core boxes in core photos, and checking reported composite lengths and count-per-second values.

For additional information regarding the company's Larocque East project, including the current mineral resource estimate for IsoEnergy's Hurricane deposit, please see the technical report entitled "Technical Report on the Larocque East Project, Northern Saskatchewan, Canada," dated Aug. 4, 2022, available on the company's profile on SEDAR+.

About IsoEnergy Ltd.

IsoEnergy is a leading, globally diversified uranium company with substantial current and historical mineral resources in top uranium mining jurisdictions of Canada, the United States and Australia at varying stages of development, providing near-, medium- and long-term leverage to rising uranium prices. IsoEnergy is currently advancing its Larocque East project in Canada's Athabasca basin, which is home to the Hurricane deposit, boasting the world's highest-grade indicated uranium mineral resource.

IsoEnergy also holds a portfolio of permitted past-producing, conventional uranium and vanadium mines in Utah with a toll-milling arrangement in place with Energy Fuels. These mines are currently on standby, ready for rapid restart as market conditions permit, positioning IsoEnergy as a near-term uranium producer.

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