Fortuna Mining Corp. (NYSE: FSM) (TSX: FVI) is pleased to report updated exploration drilling results from the Kingfisher and Sunbird deposits at the Séguéla Mine in Côte d’Ivoire.

Paul Weedon, Senior Vice President of Exploration at Fortuna, commented, “A successful infill drill program was completed at Kingfisher, with several notable intersections confirming the broad nature of the mineralization, including 4.5 g/t Au over an estimated true width of 37.4 meters from 79 meters in drill hole SGRD2363. Exploration has now turned to further extending the strike and depth at Kingfisher, successfully intersecting mineralization 300 meters below surface and a further 250 meters along strike.”

Mr. Weedon continued, “Deep exploration drilling testing the southern extent of Sunbird has continued to return excellent results while upgrading the geological confidence and expanding the mineralized envelope, with results including 8.5 g/t Au over an estimated true width of 7.0 meters from 566 meters in drill hole SGRD2431. In addition, drilling has recently identified near surface shallow mineralization approximately 180 meters into the footwall, with results including 2.1 g/t over an estimated true width of 8.4 meters from 32 meters in drill hole SGRD2418 and 5.6 g/t Au over an estimated true width of 4.9 meters from 98 meters in drill hole SGRD2422. Mineralization remains open at depth and along strike.”

Kingfisher Deposit Drilling Highlights

An additional 78 drill holes, totaling 13,262 meters, have been completed at the Kingfisher Deposit (refer to Figure 1) as part of the resource confidence infill and extension drill program (refer to Figure 2). Drilling to test the emerging down-plunge potential to the north is advancing with two drill rigs in operation. Highlights include drill hole SGRD2501, which intersected 12.7 g/t Au over an estimated true width of 0.9 meters as part of a wider interval of 1.6 g/t Au over an estimated true width of 9.4 meters from 362 meters depth, approximately 300 meters vertically. This is the deepest drilling to date at Kingfisher, with mineralization remaining open along strike and at depth along a greater than one kilometer strike. Drilling is planned to continue through 2025.

The apparent moderate northerly plunge interpreted for the Kingfisher mineralization is atypical for Séguéla, where a moderate southerly plunge is more common. This variation is interpreted as being related to localized dextral movement along the main shear corridor.

Figure 1: Location of the Kingfisher and Sunbird deposits, Séguéla Mine, Côte d’Ivoire

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

Sunbird Deposit Drilling Highlights

An additional 41 drill holes, totaling 17,532 meters, have been completed at the Sunbird Deposit (refer to Figure 1) as part of the resource confidence infill and extension program (refer to Figure 3). The program had two objectives: first, to infill and upgrade resource confidence for an approximate 600-meter section along strike of the current underground resource; and second, to extend and expand the down-plunge extension a further 300 meters south.

Drilling on the main shoot has continued to intersect high grades along the projected plunge, with drill-defined mineralization now extending more than 1.1 kilometers down plunge, approximately 700 meters below surface. Results include 11.2 g/t Au over an estimated true width of 5.6 meters from 479 meters in drill hole SGRD2409. Results such as 10.4 g/t Au over an estimated true width of 4.9 meters from 483 meters in drill hole SGRD2427, and 12.2 g/t Au over an estimate true width of 4.9 meters from 420 meters in drill hole SGRD2219, highlight the emergence of a second high grade shoot extending at least 800 meters down plunge from the bottom of the currently defined pit. Mineralization remains open at depth and along strike, with drilling scheduled to continue until the end of 2025.

Drilling targeting the deep extensions also intersected near-surface mineralization approximately 180 meters into the footwall. Further drilling will be carried out to determine the mineralized extent, which is presently open over a 400-meter strike length, and relationship to Sunbird as well as historic small-scale artisanal workings further south along strike. Results include 5.6 g/t Au over an estimated true width of 4.9 meters from 98 meters in drill hole SGRD2422, and 14.7 g/t Au over an estimated true width of 2.8 meters from 32 meters in drill hole SGRD2218.

Figure 3: Sunbird Deposit long-section – looking west, Séguéla Mine, Côte d’Ivoire

Quality Assurance & Quality Control (QA – QC)

All drilling was completed under supervision of Fortuna personnel, following standardized procedures and methodologies.

Reverse Circulation Drilling

RC 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 exclude groundwater inflow. If water ingress exceeded the 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 produce a 12.5% representative sample for laboratory submission. The remaining 87.5% samples were stored at the drill site until assay results were received and validated. Coarse reject samples from mineralized samples corresponding to significant intervals are retained and stored on-site at the Company´s core yard.

Diamond Drilling

DD drill holes started with HQ sized diameter, before reducing to NQ diameter diamond drill bits on intersecting fresh rock. The core was logged, marked for sampling in standard one-meter lengths or to a geological boundary, then cut into equal halves using a diamond saw. One half was retained in the original core box and stored in a secure location at the Company core yard at the project site. The other half was sampled, catalogued, and placed into sealed bags and securely stored at the site until shipment.

Sample Transport and Analysis

All RC and DD samples were transported by Company vehicle or commercial courier to ALS Global’s preparation laboratory in Yamoussoukro, Cote d’Ivoire or Bureau Veritas’ preparation and analytical laboratory in Abidjan, Cote d’Ivoire. Sample pulps prepared by ALS Global were then transported via commercial courier to ALS Global’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 >10 ppm Au were reanalyzed using a 50-gram charge and fire assay with a gravimetric finish.

Quality Control

Quality control procedures included systematic insertion of blanks, duplicates, and certified reference standards into the sample stream. Both ALS Global and Bureau Veritas laboratories also inserted their own quality control samples.

Qualified Person

Paul Weedon, Senior Vice President Exploration for Fortuna Mining Corp., is a Qualified Person as defined by National Instrument 43-101 being a member of the Australian Institute of Geoscientists (Membership #6001). Mr. Weedon has reviewed and approved the scientific and technical information contained in this news release. He has also 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 examining 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.

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

^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>