Omai Gold Files NI 43-101 Technical Report Supporting an Updated Mineral Resource Estimate on Its Omai Gold Property in Guyana

Toronto, Ontario Omai Gold Mines Corp. (TSXV: OMG) (OTCQB: OMGGF) ("Omai Gold" or the "Company") announces that a National Instrument 43-101 Technical Report dated October 9, 2025 (the "Report") has been filed on the SEDAR+ website www.sedarplus.ca in support of the updated Mineral Resource Estimate ("MRE") announced August 25, 2025 on its 100%-owned Omai Gold Property in Guyana. The MRE includes an expansion to the Wenot Deposit and incorporates the previously disclosed Gilt Creek Deposit. Most significantly, for the Wenot Mineral Resource Estimate ("MRE"), the Inferred MRE increased 130% to 3,717,000 oz grading 1.82 g/t Au, contained in 63.4 million tonnes ("Mt"), and the Indicated MRE increased 16% to 970,000 oz grading 1.46 g/t Au, contained in 20.7 Mt. The Report was prepared under the supervision of Eugene Puritch, P.Eng., FEC, CET of P&E Mining Consultants Inc., who is independent of the Company and a Qualified Person in accordance with NI 43-101.

The Omai Property hosts two orogenic gold deposits: the shear-hosted Wenot Deposit and the adjacent intrusive-hosted Gilt Creek Deposit. On August 25, 2025, the Company issued a news release announcing the update combined MRE (over the February 2024 MRE) with the following highlights:

• 2,121,000 ounces of gold (Indicated MRE), a 7% increase, averaging 2.07 g/t Au in 31.9Mt and
• 4,382,000 ounces of gold (Inferred MRE), a 92% increase, averaging 1.95 g/t Au in 69.6Mt

Wenot Deposit (a constrained pit and underground approach is applied)

• 970,000 oz of gold in 20.7Mt (Indicated), a 16% increase in ounces over the Feb 2024 MRE
• 3,717,000 oz of gold in 63.4Mt (Inferred), a 130% increase in ounces
• 1.46 g/t Au grade of Indicated MRE, a 1.4% decrease*
• 1.82 g/t Au grade of Inferred MRE, an 8.5% decrease*
  *Increased gold price assumption to $2,500/oz from $1,850/oz allowed cutoff lower to 0.30 g/t Au from 0.35 g/t Au, resulting in lower average grades however increased ounces
• ~60% above 350m depth from surface
• ~30% of Wenot MRE is west of the historical open pit, an area considered to be well suited to initial mining
• Expansion potential is evident along a minimum 2.5 km length of the host Wenot shear corridor, including within, adjacent to, below, and along strike

Gilt Creek Deposit (an underground mining approach is applied)

• 1,151,000 ounces of gold (Indicated) averaging 3.22 g/t Au, in 11.1Mt (Feb 2024 MRE)
• 665,000 ounces of gold (Inferred) averaging 3.35 g/t Au, in 6.2Mt (Feb 2024 MRE)
• Hosted within a 500m by 300m quartz diorite intrusive "Omai stock" that produced 2.4 million ounces of gold (1993 to 2005) from the upper 250m
• Located 500m north of the Wenot Deposit and below the past-producing Fennel open pit
• Characterized by very wide sub-horizontal zones of gold mineralization
• Open to depth and holds demonstrated potential for lateral expansion

Full details are presented in the Report filed on SEDAR+ and the Company's website https://omaigoldmines.com/site/assets/files/5486/2025_omg_wenot_umre_tech_report_final_20251009.pdf.

Qualified Persons

Elaine Ellingham, M.Sc., P.Geo. and Eugene Puritch, P.Eng., FEC, CET, President of P&E Mining Consultants Inc., both Qualified Persons (QPs) under National Instrument 43-101 "Standards of Disclosure for Mineral Projects", have approved the technical information contained in this news release. Ms. Ellingham is not considered to be independent for the purposes of National Instrument 43-101. The Mineral Resource Estimate, including verification of the data, was under the supervision of Mr. Puritch, who is independent for the purposes of National Instrument 43-101.

About Omai Gold Mines Corp.

Omai Gold Mines Corp. is a Canadian gold exploration and development company focused on rapidly expanding the two orogenic gold deposits at its 100%-owned Omai Gold Project in mining-friendly Guyana, South America. The Company has established the Omai Gold Project as one of the fastest growing and well-endowed gold camps in the prolific Guiana Shield greenstone belt. In February 2024, the Company announced a Preliminary Economic Assessment ("PEA"), reported in an NI 43-101 Report filed in April 2024, available on www.sedarplus.ca. The 2024 PEA contemplated an open pit-only development scenario and included only 45% of the Omai Gold Project MRE. More recently, the Company announced an updated, significantly increased Mineral Resource Estimate on August 25, 2025, and is commencing the preparation of an updated PEA that is expected in early 2026. Four drills are currently active on the property: at Wenot the focus is to optimize the upcoming PEA, to further test the limits of the deposit, including both east and west, and to upgrade some of the large Inferred Resource to Indicated. Additional drilling will explore certain known gold occurrences for possible near surface higher-grade satellite deposits.

The Omai Gold Mine produced over 3.7 million ounces of gold from 1993 to 2005², ceasing operations when gold was below US$400 per ounce. The Omai site significantly benefits from existing infrastructure and will soon be connected to the two largest cities in Guyana, Georgetown and Linden, via paved road.

¹NI 43-101 Technical Report dated October 9, 2025 titled
"Updated Mineral Resource Estimate and Technical Report on the Omai Gold Property, Potaro Mining District No.2, Guyana" by P&E Mining Consultants Inc. is available on SEDAR+ and on the Company's website.
²Past production at the Omai Mine (1993-2005) is summarized in several Cambior Inc. documents available on SEDARplus.ca, including March 31, 2006 AIF and news release August 3, 2006.

Cautionary Note Regarding Forward-Looking Statements

This news release includes certain "forward-looking statements" under applicable Canadian securities legislation. Forward-looking statements include, but are not limited to, statements with respect to the timing of completion of the drill program, and the potential for the Omai Gold Project to allow Omai to build significant gold Mineral Resources at attractive grades, and forward-looking statements are necessarily based upon a number of estimates and assumptions that, while considered reasonable, are subject to known and unknown risks, uncertainties and other factors which may cause the actual results and future events to differ materially from those expressed or implied by such forward-looking statements. Such factors include, but are not limited to general business, economic, competitive, political and social uncertainties; delay or failure to receive regulatory approvals; the price of gold and copper; and the results of current exploration. Further, the Mineral Resource data set out in this news release are estimates, and no assurance can be given that the anticipated tonnages and grades will be achieved or that the indicated level of process recovery will be realized. There can be no assurance that forward-looking statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Accordingly, readers should not place undue reliance on forward-looking statements. The Company disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

Cautionary Note Regarding Mineral Resource Estimates

Until mineral deposits are actually mined and processed, Mineral Resources must be considered as estimates only. Mineral Resource Estimates that are not Mineral Reserves have not demonstrated economic viability. The estimation of Mineral Resources is inherently uncertain, involves subjective judgement about many relevant factors and may be materially affected by, among other things, environmental, permitting, legal, title, taxation, socio-political, marketing, or other relevant risks, uncertainties, contingencies and other factors described in the Company's public disclosure available on SEDAR+ at www.sedarplus.ca. The Inferred Mineral Resource in this estimate has a lower level of confidence than that applied to an Indicated Mineral Resource and must not be converted to a Mineral Reserve. It is reasonably expected that the majority of the Inferred Mineral Resource could be upgraded to an Indicated Mineral Resource with continued exploration. The accuracy of any Mineral Resource Estimates is a function of the quantity and quality of available data, and of the assumptions made and judgments used in engineering and geological interpretation, which may prove to be unreliable and depend, to a certain extent, upon the analysis of drilling results and statistical inferences that may ultimately prove to be inaccurate. Mineral Resource Estimates may have to be re-estimated based on, among other things: (i) fluctuations in mineral prices; (ii) results of drilling, and development; (iii) results of future test mining and other testing; (iv) metallurgical testing and other studies; (v) results of geological and structural modeling including block model design; (vi) proposed mining operations, including dilution; (vii) the evaluation of future mine plans subsequent to the date of any estimates; and (viii) the possible failure to receive required permits, licenses and other approvals. It cannot be assumed that all or any part of a "Inferred" or "Indicated" Mineral Resource Estimate will ever be upgraded to a higher category. The Mineral Resource Estimates disclosed in this news release were reported using Canadian Institute of Mining, Metallurgy and Petroleum Definition Standards for Mineral Resources and Mineral Reserves (the "CIM Standards") in accordance with National Instrument 43-101- Standards of Disclosure for Mineral Projects of the Canadian Securities Administrators ("NI 43-101").

Cautionary Statements to U.S. Readers

This news release uses the terms "Mineral Resource", "Indicated Mineral Resource" and "Inferred Mineral Resource" as defined in the CIM Standards in accordance with NI 43-101. While these terms are recognized and required by the Canadian Securities Administrators in accordance with Canadian securities laws, they may not be recognized by the United States Securities and Exchange Commission. The "Mineral Resource" Estimates and related information in this news release may not be comparable to similar information made public by U.S. companies subject to the reporting and disclosure requirements under the United States federal securities laws and the rules and regulations thereunder.

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