Mr. Darren Hall reports

CALIBRE ANNOUNCES INITIAL HIGH-GRADE DRILL RESULTS AT ITS EASTERN BOROSI MINE COMPLEX; DRILLING INTERSECTS 12.9 G/T GOLD OVER 8.5 METRES INCLUDING 23.30 G/T GOLD OVER 1.6 METRES

Calibre Mining Corp. has released its drill results from the resource conversion and expansion program within its 100-per-cent-owned, Eastern Borosi mine complex, located in northeastern Nicaragua.

Highlights of the Eastern Borosi infill drill program:

• 12.9 grams per tonne Au over 8.5 metres estimated true width (ETW) including 23.30 g/t Au over 1.6 metres ETW and 35.50 g/t Au over 1.24 metres ETW in hole BL-23-097;
• 10.61 g/t Au over 7.2 metres ETW including 27.47 g/t Au over 2.3 metres ETW in hole BL-23-099;
• 7.1 g/t Au over 5.0 metres ETW including 14.75 g/t Au over 2.3 metres in hole BL-23-102.

Note: Estimated true widths for reported vein intercepts are based on 3-D models of the individual veins. Estimates are determined in cross-section by measuring the modelled vein thickness perpendicular to the vein margins and through the mid-point of the drill hole intercept. Percentage-based differences between individual ETWs and down-hole interval lengths will vary between drill holes depending on drill hole inclination, variations in vein strike and dip, and overall geometries of the different vein systems.

Darren Hall, president and chief executive officer of Calibre, stated: "Following the successful commencement of a new satellite mining operation from our high-grade Guapinol open pit at Eastern Borosi (see news release dated April 18, 2023), today's results reinforce the potential for discovery and resource expansion within the 176-square-kilometre Eastern Borosi land package. With a solid initial resource base coupled with a rejuvenated approach to discovery and expansion within the district, I anticipate we will continue to have success given the numerous high-priority targets. Importantly, these results lie outside of our current reserves and thus any success had here will contribute to mine life extension.

"A recently completed cross-country road network combined with the new satellite mining operation, present expanded opportunities in the region for Calibre. Over the past few years, we have significantly expanded our 100-per-cent-owned Atlantic region land package, now at 7,281 square kilometres. Prior to the B2Gold transaction in 2019, the company discovered the near-surface, Primavera copper-gold porphyry system where the company is advancing target delineation work. Additionally, Calibre owns a 100-per-cent interest in the Cerro Aeropuerto project in the past-producing Siuna district, which, presents another opportunity for expansion or additional discovery in the region."

About Eastern Borosi and Atlantic mineral concessions

The 176 square km Eastern Borosi land package consists of open pit and underground known resources including Riscos de Oro, East Dome, Blag and La Luna, in addition to the now operating, Guapinol/Vancouver open pit mine. These deposits consist of numerous low-sulphidation gold-silver vein systems. Currently, Eastern Borosi hosts an indicated mineral resource of 1.031 million tonnes at 8.48 g/t gold for contained gold of 281,000 ounces and an inferred mineral resource of 2.895 million tonnes at 3.18 g/t gold for contained gold of 296,000 ounces (refer to the annual information form for the year ended Dec. 31, 2022, dated March 17, 2023).

Surrounding the Eastern Borosi project is a large 7,281 square km land package 100 per cent owned by Calibre Mining. The land package is prospective for porphyry, skarn and epithermal vein deposits, which include the Primavera and Cerro Aeropuerto deposits, both of which contain an inferred mineral resource. Primavera is a gold-copper porphyry deposit which hosts an inferred mineral resource of 44,974,000 tonnes at 0.54 g/t gold, 1.15 g/t silver and 0.22 per cent copper for 782,000 ounces of gold, 1,661,000 ounces of silver and 218,670,000 pounds of copper, yielding a gold grade equivalent of 0.84 g/t (see NI 43-101 technical report dated Jan. 31, 2017). Cerro Aeropuerto contains gold- and base metal-bearing quartz and replacement style skarn mineralization which hosts an inferred mineral resource of 6,052,000 tonnes at 3.64 g/t gold and 16.16 g/t silver for 707,750 ounces of gold and 3,144,500 ounces of silver yielding a gold grade equivalent of 3.89 g/t (see NI 43-101 technical report dated April 11, 2011).

Quality assurance/quality control

Calibre maintains a quality assurance/quality control (QA/QC) program for all its exploration projects using industry best practices. Key elements of the QA/QC program include verifiable chain of custody for samples, regular insertion of certified reference standards and blanks, and duplicate check assays. Drill core is halved and shipped in sealed bags to Bureau Veritas in Managua, Nicaragua, an independent analytical services provider with global certifications for quality management systems ISO 9001:2008, environmental management: ISO14001 and safety management OH SAS 18001 and AS4801. Prior to analysis, samples are prepared at Veritas's Managua facility and then shipped to its analytical facility in Vancouver, Canada. Gold analyses are routinely performed via fire assay/AA finish methods. For greater precision of high-grade material, samples assaying 10 g/t Au or higher are reassayed by fire assay with gravimetric finish. Analyses for silver and other elements of interest are performed via induction coupled plasma (ICP).

Qualified person

The scientific and technical information contained in this news release was approved by David Schonfeldt, PGeo, Calibre Mining's corporate chief geologist and a qualified person under National Instrument 43-101.

About Calibre Mining Corp.

Calibre Mining is a Canadian-listed, Americas-focused, growing mid-tier gold producer with a strong pipeline of development and exploration opportunities across Nevada and Washington in the United States and Nicaragua. Calibre is focused on delivering sustainable value for shareholders, local communities and all stakeholders through responsible operations and a disciplined approach to growth. With a strong balance sheet, a proven management team, strong operating cash flow, accretive development projects and district-scale exploration opportunities Calibre will unlock significant value.

We seek Safe Harbor.