Mr. Philip Williams reports

ISOENERGY RESUMES SUMMER DRILLING AT HURRICANE SOUTH TREND WITH STRONG INITIAL RESULTS; 11,075 CPS OVER 3.5 M, INCLUDING 43,160 CPS OVER 0.5 M, INTERSECTED ON SOUTH TREND

IsoEnergy Ltd. has resumed summer drilling at the Larocque East project, which hosts the high-grade Hurricane deposit, in the eastern Athabasca basin in Canada, following a temporary suspension and precautionary evacuation due to nearby wildfires (see press release dated June 29, 2026). Prior to the temporary suspension, four of a planned 20 holes were completed with all holes intersecting mineralization, including 43,160 counts per second over 0.5 metre, confirming the continuity of the newly identified L fault zone along the Hurricane South trend (Table 1). IsoEnergy's summer program is targeting 8,000 metres of diamond drilling, in up to 20 drill holes, focused on the highly prospective Hurricane South trend.

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:

• Mineralization confirmed along strike on the L fault zone: LE26-250, drilled approximately 75 metres east of the high-grade winter 2026 intercept in LE26-248 (4.21 per cent U3O8 over 3.5 m, including 11.61 per cent U3O8 over 1.0 m), intersected 11,075 counts per second over 3.5 m, including 43,160 counts per second over 0.5 m (all radioactivity reported herein are averages of three points measured over 0.5 m on drill core with an RS-125 spectrometer), extending the continuity of mineralization east of LE26-248 along strike on the L fault zone on the Hurricane South trend.
• Mineralization intersected in every completed hole: All four completed drill holes returned elevated radioactivity, reinforcing the continuity and prospectivity of the Hurricane South trend identified during the 2025 and winter 2026 results along the Hurricane South trend.
• Summer drilling resumes: Approximately 2,100 m of drilling had been drilled across four completed holes and two in progress prior to the temporary suspension due to nearby wildfire, with two additional holes in progress. The company remains on track to complete the approximately 8,000-metre, 20-hole summer program as planned.
• Strategic land position strengthened: A total of 61,830 hectares were added through staking in 2026 across the Dorado joint venture and IsoEnergy's Larocque West, Hawk, Evergreen, East Rim and Ledge projects, enhancing exposure to prospective uranium targets across the eastern Athabasca basin.
• Coverage of prospective corridors expanded: The addition of 31,293 hectares under option from GEM Oil Inc. extends the Larocque West project, increasing coverage of highly prospective structural corridors and regional exploration targets.

Dr. Dan Brisbin, vice-president of exploration, stated: "Our team is excited to resume drilling on the Hurricane South trend, where early results from the summer program continue to reinforce the prospectivity of the trend. Every completed hole has intersected anomalous radioactivity, including 43,160 counts per second over 0.5 m. These results continue to demonstrate the potential to expand Hurricane mineralization beyond the current resource footprint. With the immediate fire risk abated, we anticipate completing the 8,000-metre summer drill program as designed. In addition, we have expanded and consolidated coverage of prospective corridors though staking and through an option agreement."

Drilling resumes on the Hurricane South trend

LE26-250, drilled approximately 75 m to the east of LE26-248, which returned 4.21 per cent U3O8 over 3.5 m, including 11.61 per cent U3O8 over 1.0 m (see news release dated May 12, 2026), successfully intersected the L fault zone extrapolated from LE26-248.

The sandstone is strongly bleached with white interstitial clay below 193.0 m. A 1.5-metre (all widths reported herein are widths along the drill hole, which are not necessarily true widths) fault zone from 208.1 to 209.6 m is broken and blocky and is grey in colour due to pervasive sooty pyrite alteration, with weak hydrothermal hematite-clay alteration. Below the fault, the sandstone is more intensely bleached, with a pervasive overprint of white interstitial clay, with weak, fracture-controlled quartz dissolution localized to fracture zones. A 43.6-metre-wide interval of several local half-metre-scale zones of broken and blocky core was intersected above a fault zone, with local zones of weak quartz dissolution from 264.5 to 308.1 m. A 10.2-metre-wide fault zone was intersected from 308.1 to 318.3 m. Its top, from 308.1 to 309.6 m, is characterized by broken core with a strong sooty pyrite overprint and brick-red hematitic clay. Below the fault, the sandstone is strongly bleached with strong white interstitial clay, giving the core a chalky appearance. The base of the fault, from 312.3 to 318.3 m, is characterized by several clay-coated fractures oriented nearly parallel to the core axis, one of which is associated with a pervasive brick-red hydrothermal hematite clay. Below the fault, the sandstone remains strongly bleached with moderate white interstitial clay and overprinted by pervasive brick-red hematite to 334.8 m. Below 334.8 m, the sandstone remains relatively competent with a moderate, pervasive sooty pyrite overprint from 334.8 to 340.9 m that strengthens from 340.9 to 344.0 m. This interval returned a maximum of 43,160 counts per second over 0.5 m from 342.0 to 342.5 m (Table 1), which includes a 0.3-metre zone of unconsolidated core, within a broader interval averaging 11,075 counts per second over 3.5 m (341.0 to 344.5 m) above the unconformity at 345.4 m. The sooty pyrite overprint is moderate from 344.0 m to the unconformity. Graphitic cordierite pelite was intersected below the unconformity to 361.8 m followed by pegmatite, semipelite and pelite to the end of the hole at 449.0 m. Weakly elevated radioactivity (415 counts per second over 0.5 m) was intersected between 346.0 m and 346.5 m.

LE26-251 tested the J fault approximately 45 m to the east of LE21-107, which intersected 6.5 m averaging 20.4 per cent U3O8 from 325.5 to 332.0 m, including 3.5 m averaging 34.5 per cent U3O8 from 327.5 to 331.0 m (see news release dated Feb. 3, 2022).

The sandstone is moderately to strongly bleached below 179.0 m, coincident with moderate pervasive hematite staining, which weakens below 221.0 m. A 13.5-metre-wide fault zone from 211.3 to 224.8 m is characterized by broken, blocky and fractured core with weak fracture-controlled quartz dissolution and minor fracture-hosted hematite. From 224.8 to 278.9 m, the sandstone is relatively competent and moderately bleached, with weak to moderate interstitial clay, minor fracture zones, and 0.3 m-scale zones of increased quartz dissolution. A second, 32.1-metre-wide fault zone from 278.9 to 311.0 m is similar to the fault above but is characterized by a stronger sooty pyrite overprint, which strengthens in intervals of stronger quartz dissolution and in fracture zones. Below 311.0 m, the core is relatively competent, strongly bleached and overprinted by white interstitial clay, with minor pervasive limonite staining. A 2.5-metre-wide fault zone from 323.5 to 326.0 m is characterized by broken and blocky core throughout with strong quartz dissolution from 323.4 to 323.8 m. Below the fault, the core is moderately silicified to 328.1 m, below which the sandstone is more competent and overprinted by sooty pyrite (reduced) to the unconformity at 332.2 m. Elevated radioactivity up to 1,580 counts per second was intersected over 0.5 m from 331.5 m to 332.0 m within an interval with strong sooty pyrite alteration and within a broader interval straddling the unconformity, which averages 980 counts per second over 3.0 m from 331.0 m to 334.0 m.

Semipelite to pelite was intersected below the unconformity, with graphitic pelite from 344.4 m to the end of hole at 398.0 m. A 3.4-metre fault was intersected within the graphitic pelite from 353.4 to 356.8 m. The intersection of graphitic pelite and the interpreted target fault in the basement suggests LE26-251 was positioned slightly hangingwall of the optimal target.

LE26-252 was drilled 30 m east of LE26-234, which intersected 1.00 per cent U3O8 over 1.5 m (332.0 to 333.5 m), including 2.75 per cent U3O8 over 0.5 m (332.0 to 332.5 m) (see news release dated May 12, 2026).

The sandstone is moderately bleached below 143.5 m. A 21.8-metre-wide fault zone from 221.0 to 242.8 m is characterized by broken and blocky core with strong quartz dissolution around fracture zones and strong white interstitial clay that gives the core a chalky appearance, with minor limonite present within fracture zones and intervals with increased quartz dissolution within the fault. Below the fault, the sandstone is more competent and strongly bleached with a weak pervasive limonite overprint from 242.8 m to 314.0 m, with limonite stronger in local fracture zones. From 314.0 m, the sandstone is strongly bleached with lesser limonite and moderate interstitial clay, with strong clay alteration closer to a 0.9-metre-wide fault zone from 316.1 to 317.0 m. The fault is characterized by broken and blocky core with increased quartz dissolution. Below the fault, from 317.0 m to the unconformity, the core is relatively competent with minor local zones of strong quartz dissolution, a weak limonite overprint and moderate to strong interstitial white clay. Minor local zones of pervasive brick-red hematite are present around fractures from 324.3 to 325.4 m. The unconformity was intersected at 329.8 m.

Below the unconformity, semipelite to pelite with intercalated pegmatite extends to the end of the hole at 419 m. The basement rocks are moderately to strongly clay altered to 337.7 m, with weakly elevated radioactivity intersected within the clay altered zone (450 counts per second over 0.5 m from 333.5 m to 334.0 m).

LE26-253 intersected the unconformity 11 m south of LE26-249 and 44 m east of LE21-103.

The sandstone is moderately to strongly bleached below 208.5 m and strongly bleached below 261.8 m, with weak to moderate interstitial clay. The core is competent to 290.0 m, below which several localized (0.2-metre to 0.5-metre scale) faults characterized by clay gouge to 314.0 m. The localized faults below 310.8 m are overprinted by brick-red hematite staining, with lesser limonite. Below the fault zone, the core is strongly bleached, weakly overprinted by sooty pyrite and is relatively competent to 329.5 m, with the exception of a 1.0-metre-wide broken and rubbly fault zone with increased quartz dissolution from 318.7 to 319.7 m. Below 329.5 m, the sandstone is overprinted by moderate to strong interstitial clay to the unconformity at 340.5 m, with a moderate pervasive hydrothermal hematite and lesser limonite overprint from 336.2 m to the unconformity. Elevated radioactivity averaging 620 counts per second over 0.5 m was recorded between 337.5 and 338.0 m, about three metres above the unconformity.

Graphitic pelite was intersected in the basement to 349.2 m, including an interval of weakly radioactivity (360 counts per second over 0.5 m between 343.0 and 343.5 m). Intercalated pelite and semipelite were intersected below the graphite to the end of the drill hole at 401.0 m.

LE26-253 tested ideal target as the drill hole intersected the L fault at the unconformity.

Expansion and consolidation of land tenure

IsoEnergy has expanded and consolidated its land position along prospective corridors in the eastern Athabasca basin, staking approximately 61,830 hectares across 32 claims. In addition, the company has optioned the Larocque West Extension claims from GEM Oil, comprising approximately 31,293 hectares across 20 claims. The optioned claims are notably underexplored for uranium mineralization: While four drill holes have been completed on the Larocque West Extension claims, only two targeted uranium.

Concurrently, IsoEnergy has elected to divest its Bulyea River property. Following the divestment, recent staking and the GEM Oil option, IsoEnergy now holds or has access to approximately 344,812 hectares of land in the eastern Athabasca basin, including its interest in the joint venture with Purepoint Uranium Group Inc.

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 to radioactivity measured downhole with Mt. Sopris 2PGA-1000 and AlphaNuclear high-flux (ANHF) probes, 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.

We seek Safe Harbor.