San Lorenzo Reports Assay Results from Epithermal Focused Drilling on the “San Juan Extension” of the Arco de Oro Epithermal System and Provides Exploration and Drilling Update

CALGARY / June 29, 2026 / San Lorenzo Gold Corp. ("San Lorenzo" or the "Corporation") (TSXV: SLG and OTC: SNLGF) is pleased to announce that it has significantly expanded the mineralized footprint and confirmed key strike extensions on the Salvadora property.

Highlights:

• Assay results from four holes have been received which were drilled on the “San Juan Extension”
  • a northwest extension to the Arco de Oro “Core Zone”.
• The four holes were designed to test the epithermal vein system previously intersected by San Lorenzo in the Arco Core Zone located approximately 3.5 kilometers (“km”) to the southeast.
• Specifically, the four holes tested the system between 3.4 km and 3.9 km northwest of the nearest hole previously drilled on the Arco de Oro epithermal trend.
• These results significantly expand the known footprint of the epithermal system at Arco de Oro.
• The four holes were designed to test shallow epithermal mineralization and not large porphyry targets (as drilled by holes SAL-10-25 and SAL-09-25 - see SLG release dated June 4, 2026).
• Step-outs from holes SAL-10-25 and SAL-09-25 - to test continuity of the porphyry system - are included in the upcoming drilling program due to commence within approximately 7 days.
• The potential for significant porphyry mineralization at San Juan exists requiring further testing.

All four drill holes intersected the epithermal vein system that extends to surface, together with mineralized surrounding rock, generating the following results:

• SAL-11-25:
  • 18.9m at 1.06g/t Au from 48.3m, including 1.6m at 5.68g/t Au
• SAL-12-25:
  • 21.5m at 1.32g/t Au from 68.5m, including 3.1m at 5.82g/t Au
  • 45m at 1.24g/t Au from 113.5m, including 4.6m at 5.22g/t Au & 3.0m at 5.68g/t Au
• SAL-13-25:
  • 23m at 1.41g/t Au from 31.5m, including 1.2m at 9.52g/t Au
  • 12m at 1.15g/t Au from 95.5m
  • 8.3m at 1.71g/t Au from 174.2m
• SAL-14-25:
  • 13.3m at 1.56g/t Au from 35.2m, including 1.4m at 9.85g/t Au

The four holes have confirmed the presence of epithermal mineralization over an additional 0.5 km of strike at San Juan, which is located ~3.4 km to the northwest of the Arco Core area. Previous drilling at the Arco Core area had already defined mineralization over ~1 km of strike. Drilling has now defined mineralization over a very significant strike length (from the Arco Core Zone to the San Juan extensions). Follow-up drilling is required to confirm continuity between the two.

Importantly, when the available geological information, including drilling, mapping, rock chips, geophysical surveys and artisanal workings is viewed together, it indicates the potential for mineralization over a cumulative potential strike length of over 7.5 km as the epithermal system remains open and untested further to the northwest of San Juan. Surface artisanal workings continue for an additional 2.6 km along trend within San Lorenzo’s Salvadora land package. Follow-up drilling is required to test the system to the northwest to establish the overall continuity and extent of mineralization on Arco de Oro’s epithermal system.

San Lorenzo believes that formation of the epithermal systems are related to intrusive features suggested by chargeability and resistivity anomalies evident on San Lorenzo’s historic (2014 -2018) and recent (2025) geophysical induced polarization (“IP”) lines – a belief which has been confirmed by the recent drilling of holes SAL 09-25 and SAL 10-25 which appear to have penetrated the upper gold-rich section of a mineralized porphyry copper-gold system.

Terence Walker, San Lorenzo’s VP of Exploration, commented: “We have long believed that the epithermal vein systems at Salvadora – especially at the Arco de Oro and Tres Amigos targets – are associated with large porphyritic intrusives and their associated hydrothermal events similar in type and age to those hosting the ore deposits at the producing El Salvador mine, located 15 km to the northeast. The intercepts encountered in these last 4 holes coincide precisely with our geological model. We have cut numerous intercepts in the upper epithermal system that appear to be associated with several nearby anomalies identified on our IP lines, a conclusion further reinforced by the results of recently drilled holes 9 and 10 at San Juan.

Al Kroontje, CEO of San Lorenzo, commented, “We’re pleased with the results of the drill holes reported today. They help confirm the very significant strike length of the shallow epithermal vein mineralization at Arco de Oro. While the company is also pleased with the recent bulk-tonnage-style mineralization intercepted nearby, we recognize that the higher-grade veins near surface have the potential to host a significant gold-silver resource in their own right. These holes were drilled specifically to test the shallow, epithermal vein system rather than the deeper, intrusive-related, portion of the system. While Phase 7 drilling will be more focused on bulk tonnage targets, it’s gratifying to see that this richly endowed project also has the potential for high-grade mineralization.”

The images below illustrate:

1) the overall Arco de Oro trend with the locations of the Arco Core Zone and the San Juan Extension shown relative to each other – including an image (inset) of the artisanal workings visible at surface; and

2) A collar location plan indicating the location of the four holes reported on in this news release and their locations relative to holes SAL 09-25 and SAL 10-25.

Image 1: Arco de Oro Trend

Image 2: Collar plan of reported drilling results at the San Juan Extension Assay results from the four holes are presented in table form and section illustration on Tables and Figures 1 through 4 below:

Table 1: SAL 11-25 Assay Results

Figure 1: SAL 11-25 Section

Table 2: SAL 12-25 Assay Results

Figure 2: SAL 12-25 Section

Table 3: SAL 13-25 Assay Results

Figure 3: SAL 13-25 Section

Table 4: SAL 14-25 Assay Results

Figure 4: SAL 14-25 Section

Exploration and Drilling Update

Since completing the Phase 6 drilling program, San Lorenzo has been conducting extensive soil and rock sampling at each of the Arco de Oro and Cerro Blanco targets. Similar geo-chemical work has been ongoing on the newly acquired lands east and south of the Cerro Blanco target. In addition, an extensive IP program comprised of a minimum of 50 additional line kms of IP surveying has been initiated.

San Lorenzo is in possession of all permits required to commence the next - Phase 7 - drilling program at Salvadora. Drill-pad construction commenced approximately 10 days ago, and the first drilling rig is expected to be mobilized imminently.

The Phase 7 drilling program will initially start at Cerro Blanco. Holes are designed to follow up on the very positive results from holes SAL 01-25 and SAL 04-25. Drilling is also planned to test additional IP anomalies that have been defined at Cerro Blanco - specifically to help build an understanding of the geometry of the Cerro Blanco discovery. In addition to drilling at Cerro Blanco, drilling on the Arco de Oro target is a high priority. Drilling will be ramped up with the company working towards having 3 rigs drilling on the Salvador project.

San Lorenzo is already well funded to undertake an extensive and aggressive exploration program that is expected to continue for an extended period. San Lorenzo expects to provide continual updates to the market with respect to this drilling program.

Qualified Person

The scientific and technical information contained in this news release has been reviewed and approved by Terence Walker, M.Sc., P. Geo., the VP of Exploration of San Lorenzo who is a "qualified person" within the meaning of National Instrument 43-101.

Testing Procedures

Samples consisting of 50% of the HQ core are delivered to the ALS Laboratories in Copiapó by San Lorenzo staff for preparation which consists of drying and crushing to a 2 mm mesh and then pulverized. The sample material is then delivered to ALS’s facilities in Lima, Peru for gold analysis using the fire assay method. Samples were also analyzed by aqua-regia digestion to analyze for other elements including Ag and Cu. San Lorenzo notes that the correlation between sample intervals and true widths are unknown as the systems are still being modeled.

Drill Hole and Assay Data

Drill hole data and individual assay results from each of the holes presented in this news release can be viewed on Appendix “A” to this news release and are also available on San Lorenzo’s website:

www.sanlorenzogold.ca under the Salvadora sub-heading “Drill Hole and Assay Data”.

About San Lorenzo

San Lorenzo is focused on advancing its flagship Salvadora property located in Chile’s mega-porphyry belt. Drilling results at Salvadora - from 4 different targets so far - have convinced management that several gold and copper enriched epithermal and/or porphyry style systems may be contained within the Salvadora property.

For further information, please contact:

Terence (Terry) Walker, VP Exploration Al Kroontje Email: [email protected] Email : [email protected] Ph: + 56 9 5179 5902 Ph : +1 403 607 4009 Roger Blair or Jeff Wilson, Acuity Advisory Corp.

Email: [email protected] Ph: +1 604 351 0025 or +1 604 837 5440

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

Cautionary Note Regarding Forward-Looking Information

This news release may contain forward-looking information that involves substantial known and unknown risks and uncertainties, most of which are beyond the control of San Lorenzo. All statements included herein other than statements of historical fact are forward-looking information Such forward-looking information involves various risks and uncertainties. There can be no assurance that such information will prove to be accurate, and actual results and future events could differ materially from those anticipated in such information. Any forward-looking statements are made as of the date of this release and, other than as required by applicable securities laws, San Lorenzo does not assume any obligation to update or revise them to reflect new events or circumstances.

Appendix “A”

Drill Hole Data

Individual Assay Results