Fortuna Mining Corp. (NYSE: FSM) (TSX: FVI) is pleased to report results from ongoing exploration drilling at the Sunbird Deposit, located at the Séguéla Mine in Côte d’Ivoire. Recent drilling has successfully extended high grade mineralization at depth and confirmed the development of a second underground shoot, further supporting the potential for resource growth and mine life extension.

Paul Weedon, Senior Vice President of Exploration at Fortuna, commented, “Drilling at Sunbird has been very successful in expanding the underground potential, with the deepest holes to date intersecting multiple high grade intervals, including 5.2 g/t Au over an estimated true width of 6.3 meters from 787 meters in drill hole SGRD2460. This result extends the central mineralized zone a further 150 meters down plunge, where it remains open.” Mr. Weedon continued, “Drilling has also been very successful in extending the lower shoot a further 200 meters down plunge, with highlights including 6.0 g/t over an estimated true width of 11.9 meters in drill hole SGRD2461 from 669 meters, the deepest hole completed on this shoot to date, where it also remains open.” Mr. Weedon concluded,

“With over 1.5 kilometers of high grade strike now defined below Sunbird, we have initiated an underground study while five drill rigs continue to advance drilling aimed at expanding the mineralized envelope and testing its full extent.”

Sunbird Deposit Drilling Highlights

A further 40 drill holes, totaling 15,088 meters, have been completed at Sunbird (see Figure 1) as part of the underground resource confidence infill and extension program (see Figure 2). The objectives of the program are twofold: first, to infill and upgrade resource confidence to support the ongoing underground mining study; and second, to extend and expand mineralization a further 400 meters down plunge to the south.

Drilling on the main shoot continues to intersect high grades along the projected plunge, with drill-defined mineralization now extending more than 1.3 kilometers down plunge, approximately 700 meters below surface. Results include 5.2 g/t Au over an estimated true width of 6.3 meters from 787 meters and 5.4 g/t Au over an estimated true width of 4.9 meters from 802 meters in drill hole SGRD2460.

Recent intersections such as 6.0 g/t Au over an estimated true width of 11.9 meters from 669 meters in drill hole SGRD2461 and 13.3 g/t Au over an estimate true width of 3.5 meters from 786 meters in drill hole SGRD2467, highlight the strengthening of a second high grade shoot extending at least 900 meters down plunge from the pit base.

Mineralization remains open at depth and along strike, with drilling to continue through the end of 2025.

Figure 1: Location of the Sunbird Deposit, Séguéla Mine, Côte d’Ivoire

Figure 2: Sunbird Deposit long-section – looking west, Séguéla Mine, Côte d’Ivoire

Refer to Appendix 1 for full details of the drill holes and assay results for this drill program.

Quality Assurance & Quality Control (QA – QC)

All drilling data completed by the Company utilized the following procedures and methodologies, and all drilling was carried out under the supervision of the Company’s personnel.

All reverse circulation drilling used a 5.25-inch face-sampling pneumatic hammer with samples collected into 60-liter plastic bags. Samples were kept dry by maintaining sufficient air pressure to prevent groundwater inflow. Where water ingress exceeded air pressure, RC drilling was stopped, and drilling converted to diamond core tails. Once collected, RC samples were riffle split through a three-tier splitter to yield a 12.5 percent representative sample for submission to the analytical laboratory. The remaining 87.5% portion was stored at the drill site until assay results were received and validated. Coarse reject samples corresponding to all significant mineralized samples intervals are retained and stored on-site at the Company-controlled core yard.

All diamond drilling drill holes started with HQ-sized diameter core before reducing to NQ diameter upon intersecting fresh rock. Core was logged and marked for sampling in standard one-meter intervals or to geological boundaries. Samples were then cut into equal halves using a diamond saw. One half of the core was retained in the original core box and stored in a secure location at the Company’s core yard, while the other half was sampled, placed in sealed bags, and securely stored at site until shipment.

All RC and DD samples were transported by Company vehicle or commercial courier to either the ALS Global preparation laboratory in Yamoussoukro, Cote d’Ivoire, or the Bureau Veritas preparation and analytical laboratory in Abidjan, Cote d’Ivoire. Sample pulps prepared by ALS Global were subsequently shipped via commercial courier to ALS’s facility in Ouagadougou, Burkina Faso. Routine gold analysis using a 50-gram charge and fire assay with an atomic absorption finish was completed for all samples at either ALS’s Ouagadougou laboratory or Bureau Veritas’ laboratory in Abidjan. Samples returning assays greater than 10 parts per million of gold were reanalyzed using a 50-gram charge and fire assay with a gravimetric finish.

Quality control procedures included the systematic insertion of blanks, duplicates, and certified reference standards into the sample stream. In addition, both ALS and Bureau Veritas laboratories inserted their own quality control samples to ensure analytical accuracy and precision.

Qualified Person

Paul Weedon, Senior Vice President, Exploration for Fortuna Mining Corp., is a Qualified Person as defined by National Instrument 43-101 and is a member of the Australian Institute of Geoscientists (Membership No. 6001). Mr. Weedon has reviewed and approved the scientific and technical information contained in this news release. He has verified the data disclosed, including the sampling, analytical, and test data underlying the information or opinions contained herein, by reviewing geochemical and geological databases and inspecting diamond drill core. There were no limitations to the verification process.

About Fortuna Mining Corp.

Fortuna Mining Corp. is a Canadian precious metals mining company with three operating mines and a portfolio of exploration projects in Argentina, Côte d’Ivoire, Mexico, and Peru, as well as the Diamba Sud Gold Project in Senegal. Sustainability is at the core of our operations and stakeholder relationships. We produce gold and silver while creating long-term shared value through efficient production, environmental stewardship, and social responsibility. For more information, please visit our website at www.fortunamining.com

Appendix 1: Séguéla Mine drill program details of the drill holes and assay results for Sunbird Deposit

^Notes:

1. <sup>EOH: End of hole
   2. Depths and widths reported to nearest significant decimal place
   3. NSI: No significant intercepts
   4. ETW: Estimated true width
   5. RC: reverse circulation drilling | DD: diamond drilling tail | RCD: reverse circulation drilling with diamond tail</sup>