Thunder Bay, Ontario--(Newsfile Corp. - September 28, 2026) - Thunder Gold Corp. (TSXV: TGOL) (FSE: Z25) (OTCQB: TGOLF) ("Thunder Gold" or the "Company") is pleased to announce the following infill diamond drill results from the Bench Target, at the Company's flagship Tower Mountain Property, 40 kilometres west of Thunder Bay, Ontario.

Highlights:

• TM26-217 intersected 232.5 metres averaging 0.450 g/t Au from 360.0 metres (including 33.0 metres averaging 1.383 g/t Au);
• TM26-217 supports sub-vertical continuity as interpreted and;
• Both spatial and grade correlation support the 2026 MRE model assumptions and procedures.

TM26-217 was drilled from west to east between the 3738 and Ellen Targets (Reference Table 1.0 and Figure 1.0).

TM26-217 targeted the grade interpolation limit of the January 19, 2026, Mineral Resource Estimate ("MRE") model and parallels the entire southwestern optimized pit limit (Reference Figure 2.0).

TM26-217 is 200 metres vertically below TM23-137 (42.4 metres averaging 1.106 g/t Au). Like TM23-137, gold mineralization is bisected by a late, barren, mafic dike. Higher gold grades occur at the dike contacts in both holes.

Wes Hanson, President and CEO states, "TM26-217 is the sixth hole of our infill drill program, designed to convert Inferred resources to Indicated resources along the Bench-3738-Ellen corridor. This drilling has returned an aggregate 2,040 metres averaging 0.445 g/t Au, equal to the 2026 MRE Inferred resource grade. Overall, project to date drilling suggests excellent correlation to the 2026 MRE model, both in terms of grade and mineralization limits. We expect the positive results will continue as we complete the remaining holes in advance of the MRE update in December. Drilling is concentrating on the 700 metre long by 200 metre wide core which remains open in all directions. Our deeper drill holes suggest gold grade may be increasing with depth. TM26-217 tested the optimized pit limit as designed, establishing high-grade mineralization at the current MRE interpolation limit AND extending mineralization well above the MRE cut-off grade, over 100 metres below the current pit limit."

Table 1.0 provides the location and orientation of the reported holes. Figure 1.0 is a plan view showing the location of the drill holes reported in this news release.

Table 1.0 - Bench Target - TM26-217 Location Bearing and Dip

Figure 1.0 Bench Target Drill Plan - September 28, 2026

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Table 2.0 presents the significant results of TM26-217.

Table 2.0 - TM26-217 Significant Results

True Width is estimated where sufficient data allows.

Figure 2.0 - Cross Section TM26-217 (Looking NW) 50 metre Influence

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Table 3.0 summarizes the results of all infill drill holes completed to date.

Table 3.0 - Infill Drill Highlights August 11 to September 28, 2026

True Width is estimated where sufficient data allows.

MRE Reconciliation

Reconciliation of drill results to date within the Bench Target relative to the 2026 MRE model suggest an overall grade increase relative to model predicted grades. Figure 3.0 presents a summary of model predicted grades compared to actual drilled grade for the six (6) infill drill holes completed to date. All seven holes post-date the 2026 MRE model and can be compared directly to model predicted grades to evaluate the predictive accuracy of the model.

The results to date indicate significant variation on a hole-by-hole basis, ranging from a low of -38% (TM26-214) to a high of 100% (TM26-210). This is typical and within expected tolerances on a hole-by-hole basis. On a weighted average basis, the entire population suggests that the actual drilled grades are currently trending 12.5% higher than predicted modeled grade.

The analysis excludes all mineralization extending below the 2026 MRE model base, specifically holes TM26-210 and TM23-137X, both of which intersected significant mineralization at depth.

Figure 3.0 - Model Estimated Versus Actual Drilled Grade - Resource Conversion Drilling

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Quality Assurance and Quality Control

Diamond drilling utilizes NQ diameter tooling. The core is received at the on-site logging facility where it is, photographed, logged for geotechnical, physical properties and geological data. Samples are identified, recorded, and cut in half by wet diamond saw. Half the core is sent for assay at an accredited laboratory with the remaining half core stored on site. A standard sample length of 1.5 meters is typically employed, varying only at major lithological contacts.

Certified standards and blanks are randomly inserted into the sample stream and constitute approximately 10% of the sample stream. Certified standards and blank performance is monitored with any failures evaluated and investigated to determine if said failure is a result of error during submission. Any unexplained failures are identified and the five samples preceding and following the failure are re-assayed. Commencing in 2026, duplicate pulps are prepared at a rate of 1 in every 20 samples. The duplicate pulps are sent to a second independent analytical facility for analyses.

Activation Laboratories Ltd., Thunder Bay, Ontario, ISO/IEC 17025:2017 is the primary independent analytical service provider.

AGAT Laboratories, Thunder Bay, Ontario, ISO/IEC 17025:2017 is the secondary, independent analytical facility.

Samples are, received, dried, crushed to 80% passing 2.0 mm. A 250-gram sample is split and pulverized. Samples are analyzed for gold using a 30-gram lead collection fire assay fusion (FA) with an atomic absorption (AAS) finish. All assay results greater than 5.0 g/t Au are re-assayed using a gravimetric analysis. All assays greater than 30.0 g/t Au are re-assayed using screen metallics where a representative 1000-gram sample is split sieved at 149µm. Assays are performed on the entire +149 µm fraction and two splits of the -149 µm fraction. A final assay is calculated based on the weight of each size fraction.

Qualified Person

Technical information in this news release has been reviewed and approved by Wes Hanson, P.Geo., President and CEO of Thunder Gold Corp., who is a Qualified Person under the definitions established by NI 43-101.

About the Tower Mountain Gold Property

The 7,625-hectare, 100%-owned Tower Mountain Property is beside the Trans-Canada highway, 40-km west of Thunder Bay, Ontario (pop. 120,000). Gold mineralization occurs in variably brecciated and altered rocks surrounding the calc-alkalic Tower Mountain Intrusive Complex ("TMIC"). Drilling to date has established an initial mineral resource parallel to the western contact of the intrusion representing approximately 25% of the TMIC halo.

The MRE has an effective date of January 19, 2026. A Technical Report titled "NI 43-101 Technical Report for the 2026 Mineral Resource Estimate on the Tower Mountain Project, Ontario, Canada." is available on the Company's website at www.thundergoldcorp.com and on SEDAR+ (www.sedarplus.ca) under the Company's Issuer profile.

The Report was prepared by Charley Murahwi, P.Geo., FAusIMM.; William Lewis, P.Geo., Tudorel Ciuculescu, P.Geo., and Richard Gowans, P.Eng., all of Micon International Limited ("Micon"), Toronto, Ontario, Canada. The Report was prepared in accordance with National Instrument 43-101 Standards of Disclosure for Mineral Projects ("NI 43-101") and CIM Definition Standards of Mineral Resources and Mineral Reserves.

The MRE is summarized as follows:

Tower Mountain Mineral Resource Estimate - January 19, 2026

Notes:

1. The effective date of this MRE is January 19, 2026.
2. Messrs. William Lewis, P.Geo., Charley Murahwi, P.Geo., FAusIMM, and Tudorel Ciuculescu, P.Geo. from Micon International Limited are the Qualified Persons (QPs) responsible for this MRE.
3. The MRE has been classified in the Indicated and Inferred categories. At this time, there are no Measured resources at the Tower Mountain Project.
4. The calculated gold cut-off grade is 0.19 g/t Au.
5. An average specific gravity (SG) value of 2.77 g/cm³ was used.
6. The MRE used economic assumptions for open pit mining. The following economic parameters were used for generating the cut-off grade: a gold price of US$3,000/oz, 80% recovery, open pit mining cost of US$3.0/t, processing costs of US$8.0/t, general and administration cost of US$3.5/t, transportation cost of US$2.5/oz of gold, and a royalty of 3%.
7. The open pit used slope angles of 30° in overburden and 50° in fresh rock.
8. The block model is orthogonal and has a parent block size of 5 m x 5 m x 5 m, with minimum sub-block size of 2.5 m x 2.5 m x 2.5 m.
9. The open pit optimization used a re-blocked size of 10 m x 10 m x 10 m.
10. The mineral resources described above have been prepared in accordance with the current Canadian Institute of Mining, Metallurgy and Petroleum Standards and Practices.
11. Numbers have been rounded to the nearest million tonnes and nearest thousand ounces. Differences may occur in totals due to rounding.
12. Mineral Resources are not Mineral Reserves as they do not have demonstrated economic viability. The quantity and grade of reported Inferred Mineral Resources are uncertain in nature and there has been insufficient exploration; however, it is reasonably expected that a significant portion of Inferred Mineral Resources could be upgraded into Indicated Mineral Resources with further exploration.
13. Micon QPs have not identified any legal, political, environmental, or other relevant factors that could materially affect the potential development of the mineral resources and of the estimate.

The remaining 75% of the TMIC halo demonstrates similar geology, alteration, and geophysical signatures and is untested by drilling.

A second gold trend, identified in 2026, outcrops at surface and is continuously mineralized over a 100-metre width. This gold mineralization occurs within Timiskaming-type conglomerates that have been traced for over 5.0 kilometres along a southwest trend paralleling the Thunder Lake Fault. The Company believes both targets offer opportunities to materially increase the total resource through systematic drilling.

About Thunder Gold Corp.

Thunder Gold is advancing the Tower Mountain project in Thunder Bay, Ont. -- an emerging gold system with the scale, consistency and quality to support a long-life, open-pit operation. Results from the disciplined drill programs have consistently reinforced confidence in the continuity and predictability of the discovery while highlighting significant potential for expansion across multiple zones of the Tower Mountain intrusive complex. With industry-leading drilling costs, existing infrastructure and a skilled local work force, Tower Mountain represents a rare combination of size, scalability and cost-effective growth.

At Thunder Gold, our vision is clear: to unlock a discovery that has the potential to become a transformational gold project, delivering long-term value for shareholders while contributing to the future of Canada's mining industry.

For more information about the Company please visit: www.thundergoldcorp.com.

On behalf of the Board of Directors,
Wes Hanson, P.Geo., President and CEO

NEITHER THE TSXV NOR ITS REGULATION SERVICES PROVIDER (AS THAT TERM IS DEFINED IN THE POLICIES OF THE TSXV) ACCEPTS RESPONSIBILITY FOR THE ADEQUACY OR ACCURACY OF THIS RELEASE.

The information contained herein contains "forward-looking information" and "forward-looking statements" within the meaning of applicable securities legislation (collectively, "forward-looking statements"). Forward-looking statements relate to information that is based on assumptions of management, forecasts of future results, and estimates of amounts not yet determinable. All statements, other than statements of historical fact, are forward-looking statements and are based on predictions, expectations, beliefs, plans, projections, objectives and assumptions made as of the date of this news release, including the Company's plans regarding exploring its mineral exploration properties; anticipated results of geophysical surveys, drilling programs, geological interpretations and potential mineral recovery. Any statement that involves discussions with respect to predictions, expectations, beliefs, plans, projections, objectives, assumptions, future events or performance (often but not always using phrases such as "expects", or "does not expect", "is expected", "anticipates" or "does not anticipate", "plans", "budget", "scheduled", "forecasts", "estimates", "believes" or "intends" or variations of such words and phrases or stating that certain actions, events or results "may" or "could", "would", "might" or "will" be taken to occur or be achieved) are not statements of historical fact and may be forward-looking statements.

Forward-looking statements are subject to a variety of risks and uncertainties which could cause actual events or results to differ from those reflected in the forward-looking statements, including, without limitation: risks related to failure to obtain adequate funding on a timely basis and on acceptable terms; risks related to the outcome of legal proceedings; political and regulatory risks associated with mining and exploration; risks related to the maintenance of stock exchange listings; risks related to environmental regulation and liability; the potential for delays in exploration or development activities or the completion of feasibility studies; the uncertainty of profitability; risks and uncertainties relating to the interpretation of drill results, the geology, grade and continuity of mineral deposits; risks related to the inherent uncertainty of production and cost estimates and the potential for unexpected costs and expenses; results of prefeasibility and feasibility studies, and the possibility that future exploration, development or mining results will not be consistent with the Company's expectations; risks related to the gold price and other commodity price fluctuations; and other risks and uncertainties related to the Company's prospects, properties and business detailed elsewhere in the Company's disclosure record. Should one or more of these risks and uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those described in forward-looking statements. Investors are cautioned against attributing undue certainty or reliance on forward-looking statements. These forward-looking statements are made as of the date hereof and the Company does not assume any obligation to update or revise any forward-looking statements, other than as required by applicable law, to reflect new information, events or circumstances, or changes in management's estimates, projections or opinions. Actual events or results could differ materially from those anticipated in the forward-looking statements or from the Company's expectations or projections.

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