F3 - Hits 2.5m of 10.2% U3O8 Within 3.4% over 8.5m at JR Zone

Tetra Assays: 26.5m of mineralization including 1.04% over 0.5m

Kelowna, December 15, 2025 - F3 Uranium Corp. (TSXV: FUU) (OTCQB: FUUFF) ("F3" or "the Company") is pleased to announce final assay results of the 2025 JR Zone drill program on the PLN Property including PLN25-200 (See NR March 18, 2025) which returned 8.5m of 3.4% U₃O₈, including a high grade core with 2.5m of 10.2% U₃O₈. At the Tetra Zone, assays confirm the presence of high grade uranium mineralization 55m along strike from discovery hole PLN25-205 with PLN25-217 returning a 0.5m high grade interval with 1.04% U₃O₈ within a 3.50m mineralized interval averaging 0.30% U₃O₈ from 400.0m to 403.5m. Total composite mineralization of 26.5m was intersected between 340.5 to 406.5m.

Exploration focused mainly on the area around Tetra Zone with PLN25-207 intersecting 0.06% U₃O₈ between 621.0 to 621.5m. This deep intersect is interpreted to be associated with the same shear system which hosts the Tetra Zone over 200m to the west.

Sam Hartmann, Vice President Exploration, Comment:

"We are pleased to release the final assays for JR Zone, where the last two holes for inclusion into the upcoming maiden resource estimate were completed earlier this spring. At the Tetra Zone, we are releasing the second batch of assays since the initial high grade discovery hole (PLN25-205) assays, including an interval with high grade mineralization with 1.04% over 0.5m, confirmation of additional high-grade uranium mineralization at the Tetra Zone, 55m along strike from the discovery hole. Exploration geochemistry around the Tetra Zone continues to return strongly anomalous uranium values with 0.06% U₃O₈ at depth in PLN25-217, approximately 200m away from Tetra Zone highlighting the prospectivity and size potential of the mineralized system."

PLN Property JR Zone Assay Highlights:
PLN25-200 (line 045S):

• 8.5m @ 3.4% U₃O₈ (234.0m to 242.5m), including
  • 2.5m @ 10.2% U₃O₈ (236.0m to 238.5m), further including
  • 1.0m @ 20.7% U₃O₈ (237.5m to 238.5m), and
• 5.5m @ 0.05% U₃O₈ (246.5m to 252.0m)

Broach Property Tetra Zone Assay Highlights:
PLN25-217 (line 11280S):

• 0.5m @ 0.06% U₃O₈ (340.5m to 341.0m), and
• 3.5m @ 0.07% U₃O₈ (355.0m to 358.5m), and
• 1.5m @ 0.05% U₃O₈ (361.5m to 363.0m), and
• 1.0m @ 0.07% U₃O₈ (365.0m to 366.0m), and
• 5.5m @ 0.19% U₃O₈ (369.5m to 375.0m), and
• 6.5m @ 0.14% U₃O₈ (377.5m to 384.0m), and
• 3.5m @ 0.41% U₃O₈ (388.5m to 392.0m), and
• 0.5m @ 0.11% U₃O₈ (395.5m to 396.0m), and
• 3.5m @ 0.30% U₃O₈ (400.0m to 403.5m), including
  • 0.5m @ 1.04% U₃O₈ (400.5m to 401.0m)
• 0.5m @ 0.07% U₃O₈ (406.0m to 406.5m), and

Table 1. Drill Hole Summary and Uranium Assay Results

Assay composite parameters:
1: Minimum Thickness of 0.5 m
2: Assay Grade Cut-Off: 0.05% U3O8 (weight %)
3. Maximum Internal Dilution: 2.0 m

Map 1. Tetra Zone Drill Holes with Assay Results

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Map 2. Tetra Zone Exploration Drill Holes with Assay Results

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Map 3. JR Zone Drill Holes with Assay Results

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Map 4. A1/B1 Exploration Drillholes

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Samples from the drill core are split into half sections on site. Where possible, samples are standardized at 0.5m down-hole intervals. One-half of the split sample is sent to SRC Geoanalytical Laboratories (an SCC ISO/IEC 17025: 2005 Accredited Facility) in Saskatoon, SK while the other half remains on site for reference. Analysis includes a 63 element suite including boron by ICP-OES, uranium by ICP-MS and gold analysis by ICP-OES and/or AAS.

The Company considers uranium mineralization with assay results of greater than 1.0 weight % U3O8 as "high grade" and results greater than 20.0 weight % U3O8 as "ultra-high grade".

All depth measurements reported are down-hole and true thicknesses are yet to be determined.

About the Patterson Lake North Project:

The Company's 44,613-hectare 100% owned Patterson Lake North Project (PLN) is located just within the south-western edge of the Athabasca Basin in proximity to Paladin's Triple R and NexGen Energy's Arrow high-grade uranium deposits, an area poised to become the next major area of development for new uranium operations in northern Saskatchewan. The PLN Project consists of the 4,074-hectare Patterson Lake North Property hosting the JR Zone Uranium discovery approximately 23km northwest of Paladin's Triple R deposit, the 19,864-hectare Minto Property, and the 20,675-hectare Broach Property hosting the Tetra Zone, F3's newest discovery 13km south of the JR Zone. All three properties comprising the PLN Project are accessed by Provincial Highway 955.

Qualified Person:

The technical information in this news release has been prepared in accordance with the Canadian regulatory requirements set out in National Instrument 43-101 and approved on behalf of the company by Raymond Ashley, P.Geo., President & COO of F3 Uranium Corp, a Qualified Person. Mr. Ashley has reviewed and approved the data disclosed.

This news release may refer to neighboring properties in which F3 Uranium has no interest, and the Qualified Person has been unable to verify the information from those properties. Mineralization on those neighboring properties is not necessarily indicative of mineralization on the PLN Project. For additional information on the PLN Project, please refer to the report titled "Technical Report on the Patterson Lake North Project, Northern Saskatchewan, Canada" prepared by SLR International Corporation with a signing date of January 25, 2023and an effective date of November 20, 2023 available at www.sedarplus.ca, and prepared in accordance with NI 43-101.

About F3 Uranium Corp.:

F3 is a uranium exploration company, focusing on the high-grade JR Zone and new Tetra Zone discovery 13km to the south in the PW area on its Patterson Lake North (PLN) Project in the Western Athabasca Basin. F3 currently has 3 properties in the Athabasca Basin: Patterson Lake North, Minto, and Broach. The western side of the Athabasca Basin, Saskatchewan, is home to some of the world's largest high grade uranium deposits including Paladin's Triple R project and NexGen's Arrow project.

Forward-Looking Statements

This news release contains certain forward-looking statements within the meaning of applicable securities laws. All statements that are not historical facts, including without limitation, statements regarding future estimates, plans, programs, forecasts, projections, objectives, assumptions, expectations or beliefs of future performance, including statements regarding the suitability of the Properties for mining exploration, future payments, issuance of shares and work commitment funds, entry into of a definitive option agreement respecting the Properties, are "forward-looking statements." These forward-looking statements reflect the expectations or beliefs of management of the Company based on information currently available to it. Forward-looking statements are subject to a number of risks and uncertainties, including those detailed from time to time in filings made by the Company with securities regulatory authorities, which may cause actual outcomes to differ materially from those discussed in the forward-looking statements. These factors should be considered carefully and readers are cautioned not to place undue reliance on such forward-looking statements. The forward-looking statements and information contained in this news release are made as of the date hereof and the Company undertakes no obligation to update publicly or revise any forward-looking statements or information, whether as a result of new information, future events or otherwise, unless so required by applicable securities laws.

The TSX Venture Exchange and the Canadian Securities Exchange have not reviewed, approved or disapproved the contents of this press release, and do not accept responsibility for the adequacy or accuracy of this release.

ON BEHALF OF THE BOARD,
"Dev Randhawa"
Dev Randhawa, CEO

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