Entrée Resources Ltd. (TSX:ETG) (OTCQB:ERLFF) is pleased to provide analytical results for one surface diamond drill hole and six underground DDHs completed during 2022 and 2024 at the Hugo North Extension deposit on the Entrée/Oyu Tolgoi Joint Venture property in Mongolia. Analytical results are also provided for two DDHs from the 2024 regional drilling campaign on the Shivee Tolgoi mining licence.

DRILL HOLE HIGHLIGHTS

HNE Surface Drill Holes

• UGD189B: 552 metres grading 3.11% copper equivalent, including 260 m grading 4.45% CuEq.

HNE Underground Drill Holes

• UGD871: 197 m grading 1.29% CuEq, including 89 m grading 1.59% CuEq.

• UGD873A: 279 m grading 1.22% CuEq.

• UGD876: 169.3 m grading 3.21% CuEq, including 112 m grading 3.83% CuEq.

Note: CuEq for HNE is defined in Note 3 to Tables 1 and 2 below, where details on the drill hole assay intervals are also found.

HNE DRILLING RESULTS

The new drill hole analytical results from the HNE deposit were recently made available by the Company’s joint venture partner Oyu Tolgoi LLC and include one surface DDH and five underground DDHs completed during 2024 on the Shivee Tolgoi mining licence, as well as one underground drill hole from the 2022 program. The surface drill hole was collared on the Entrée/Oyu Tolgoi JV Property and the underground drill holes were all collared from existing infrastructure on the Oyu Tolgoi mining licence and drilled towards the north or northeast onto the Entrée/Oyu Tolgoi JV Property, targeting mineralization within, or surrounding the existing footprint of the HNE deposit (Figure 1). Full details about the 2022 and 2024 drilling programs, including drill hole locations, were previously provided by Entrée on February 28, 2024 (see the news release titled, “Entrée Resources Announces Partial Drill Results for Hugo North Extension and Provides Update on Underground Development Work”) and February 27, 2025 (see the news release titled, “Entrée Announces Drill Results From Hugo North Extension and Heruga Deposits”). Table 3 and Table 4 show the collar and drilling information for HNE surface and underground drill holes, respectively, discussed in this news release.

Analytical results for one surface DDH and three underground DDHs from the 2024 drilling program at HNE are still pending. These results will be reported as they become available from OTLLC.

Significant mineralized intervals from the surface DDH and the six underground DDHs at HNE are summarized in Table 1 and Table 2, respectively, and are shown on Figure 1.

Table 1: Surface Drill Results from 2024 Drilling at the HNE Deposit¹

Table 2: Underground Drill Results from 2022 and 2024 Drilling at the HNE Deposit¹

Figure 1: Plan View of Newly Released Assay Intervals and Locations of 2022-2024 Drill Holes

Surface drill hole EGD189 was collared in approximately the centre of the surface projection of the HNE mineralized footprint and drilled very steeply towards the northwest, followed by two daughter holes EGD189A and EGD189B. After crossing through approximately 1,226 m of barren, sedimentary, and volcanic units, the drill hole intersected the top of the porphyry deposit, hosted in quartz monzodiorite in the proposed Lift 2 block cave. The following 552 m (1,226 m to 1,778 m) returned significant copper and gold mineralization within the potential Lift 2 block cave, which averaged 3.11% CuEq, including 260 m grading 4.45% CuEq, and continuing for approximately 200 m below the base of the potential Lift 2 block cave. The drill hole was ended at a drilled depth of 1,778 m, remaining in very strong copper and gold mineralization (>1.0 % CuEq).

Each of the six underground DDHs with newly reported assay results were drilled at moderate dips towards the north or northeast, targeting mineralization within the potential Lift 2 block cave, or the area immediately to the east. Drill holes UGD855, UGD871, UGD872, and UGD873A all intersected strong to moderate copper and gold mineralization starting from the point where they crossed onto the Entrée/Oyu Tolgoi JV Property, which was below the base of the potential Lift 2 block cave, and continuing in significant copper and gold mineralization to depths between approximately 100 m to 175 m below the base of the potential Lift 2 block cave. Length weighted average intervals for these drill holes are shown on Table 2.

Drill hole UGD876 was drilled approximately northwards, at a moderate dip and crossed through the eastern half of the HNE deposit on the Oyu Tolgoi mining licence before crossing onto the Entrée/Oyu Tolgoi JV Property at 224.7 m (Figure 1). The drill hole continued across the western half of the HNE deposit, returning very significant grades of copper and gold, including 112 m grading 3.83% CuEq, within a wider interval of 169.3 m grading 3.21% CuEq.

Drill hole UGD576 is the upper portion (parent hole) of daughter hole UGD576A, with grades previously reported by the Company on July 18, 2024 (see the news release titled, “Entrée Resources Announces Additional Drill Results and Provides an Update on Underground Development Work”). Drill hole UGD576 has a 51.8 m segment grading 1.12% CuEq on the Entrée/Oyu Tolgoi JV Property that was not previously provided to the Company.

The newly reported drill holes all intersected predominantly phyllic and potassic altered quartz monzodiorite, cut by occasional intervals of unmineralized biotite-granodiorite dikes (generally less than 10 m in drilled width). Total sulphide content is variable but averages around 5% and is comprised of a mix of chalcopyrite, bornite and pyrite hosted in quartz stockworks and disseminated form. Some of the highest-grade individual assays (grading around 5% to 10% CuEq) are often hosted within hydrothermal breccias, containing a majority of disseminated and coarse bornite and chalcopyrite.

Many of the drill holes reported in this and previous news releases have continued up to 200 m vertically below the base of the potential Lift 2 block cave and remained in strong copper and gold mineralization. The Company believes this could provide continuity for deeper, potential future lifts.

All Entrée/Oyu Tolgoi Joint Venture expenditures are borne by the participants in proportion to their participating interests. OTLLC contributes funds on Entrée’s behalf, with each such contribution treated as a loan to Entrée, with interest.

Table 3: HNE Surface Drill Hole Collar Details

Table 4: HNE Underground Drill Hole Collar Details

LIFT 1 PANEL 1 UNDERGROUND DEVELOPMENT

On April 16, 2025, Rio Tinto announced that Oyu Tolgoi Lift 1 underground mine ramp-up remains on track. Oyu Tolgoi is set to become the world’s fourth largest copper mine by 2030 with the operation expected to deliver average mined copper production of ~500 ktpa between 2028 and 2036. Refer to Rio Tinto’s news release dated April 16, 2025, titled “Rio Tinto releases first quarter 2025 production results” available on its website at www.riotinto.com for further details.

The Lift 1 underground mine plan incorporates the development of three panels (Panels 0, 1, and 2). In order to reach the full sustainable production rate from underground operations, all three panels need to be in production. The HNE deposit on the Entrée/Oyu Tolgoi JV Property is located in the northern portion of Panel 1.

Panel 1 underground development work on the Entrée/Oyu Tolgoi JV Property commenced in October 2024. As of April 30, 2025, OTLLC had completed ~152 equivalent metres of lateral development work. All development work was in rock classified as waste.

Work planned to be completed in 2025 in the HNE deposit footprint in line with the 2025 Oyu Tolgoi Mine Plan approved by the Mineral Resources and Petroleum Authority of Mongolia is contingent upon the transfer of the Shivee Tolgoi and Javkhlant mining licences to OTLLC as Manager on behalf of the Entrée/Oyu Tolgoi JV participants. If the transfer of the JV Licences is not achieved in the near term, lateral development work on the Entrée/Oyu Tolgoi JV Property could be delayed.

In February 2025, Entrée LLC and OTLLC executed License Transfer Agreements to govern the transfer of the JV Licences and jointly lodged the License Transfer Agreements and supporting documentation with the Mongolian tax authority for the assessment of tax on the transfer of the JV Licences in accordance with applicable laws of Mongolia. The transfer tax assessment process is ongoing. Taxes must be assessed by the Mongolian tax authority and paid before the documentation necessary to affect the transfer of the JV Licences may be submitted to MRPAM.

The Company and OTLLC remain committed to working towards the potential conversion of their existing Joint Venture Agreement into a more effective agreement of equivalent economic value for the benefit of all stakeholders including the people of Mongolia. The agreement would include a mechanism for Entrée to fulfil any obligation under Mongolian law to provide the State of Mongolia with 34% of the economic benefit that Entrée derives from the area of the JV Licences.

2024 REGIONAL DRILLING RESULTS

OTLLC has provided Entrée with analytical results for the remaining two holes from the 2024 regional drilling program: EGD184 at Ulaan Khud South and EGD193 at a prospect area approximately 3.2 kilometres to the northeast of HNE. Full details about the 2024 regional drilling program, including drill hole locations, were previously provided on February 27, 2025 (see the news release titled, “Entrée Announces Drill Results From Hugo North Extension and Heruga Deposits”).

EGD184 was drilled at the Ulaan Khud South prospect to a depth of 1,127.9 m to test a distinct chargeability anomaly that was identified by the 2023 dipole-dipole induced polarization geophysical survey. The drill hole crossed quartz monzodiorite with moderate chlorite alteration in the upper section, followed by feldspar altered dacite and hornblende-biotite andesite. The drill hole was terminated after intercepting Permian-aged Khanbogd granite. Several anomalous copper and gold mineralized intervals were intersected as shown on Table 5.

EGD193 was drilled to test an area with coincident magnetic and gravity anomalies approximately 3.2 kilometres to the northeast of the HNE deposit. The drill hole continued to a depth of 1,200 m and crossed a sequence of weakly sericite and chlorite-magnetite altered Carboniferous-aged volcanic and volcaniclastic units. These include basaltic breccia, interstratified conglomerate, siltstone-sandstone and laminated tuffaceous siltstone-mudstone, cut by rare late-stage hornblende-biotite andesite and rhyolite dykes. Except for a few isolated copper and gold anomalies, no significant assays were returned.

Table 5: Regional Exploration Drill Hole Results from 2024 Drilling

2025 HNE AND REGIONAL DRILLING UPDATES

The Entrée/Oyu Tolgoi JV Management Committee approved programs to continue drilling at HNE and testing regional prospects during 2025. At HNE, drill holes will be focused on targeting gaps in the geological model. A total of five surface drill holes totaling ~9,050 m and 19 underground drill holes totaling ~8,329 m are planned. For the regional program, OTLLC is proposing to drill nine DDH totaling ~8,520 m, comprised of two holes at Railway (~1,600 m), two holes at Heruga West (~2,180 m), two holes at Eagle (~1,940 m), and three holes at Ulaan Khud (~2,800 m).

SAMPLE PREPARATION AND ANALYSIS, QAQC AND QUALIFIED PERSON

Drill core from the seven drill holes reported for HNE and for the regional drill holes was geologically and geotechnically logged at site by OTLLC. The HNE and regional surface drill holes were collared with PQ diameter core (123 mm) and often reduced to HQ (96 mm) core diameter at depth. Underground holes at HNE were collared using HQ diameter and occasionally reduced to NQ (76 mm) at depth. All core was saw-cut on site before being bagged and shipped to the laboratory. Sample lengths generally averaged approximately 2.0 m and core recovery was recorded as being very good (>95% recovery), except in localized areas of faulting/fracturing.

Core from HNE and the regional drilling was shipped to ALS Laboratory in Ulaanbaatar, Mongolia, for sample preparation. ALS is independent of OTLLC, Rio Tinto and Entrée. At ALS the samples were crushed to <2mm and pulverized to 75μm, then the pulps were shipped directly to ALS in Perth for analyses. Samples were analyzed for gold by ICP-MS. Samples above approximately 0.03 g/t gold were further analyzed for gold by a 30-gram fire assay with an ICP finish. Samples were also analyzed for copper, silver and molybdenum, along with eight additional elements by 4-acid digestion, ICP-MS/AES multi-element analysis. Copper samples greater than approximately 1.0% were further analyzed by ore grade ICP ES/MS method.

OTLLC follows a rigorous quality assurance/quality control program for the sampling programs that includes the regular insertion of standards, blanks and duplicates into the sample stream. The QP is not aware of any drilling, sampling, recovery, or other factors that could materially affect the accuracy or reliability of the data referred to in this disclosure.

The scientific and technical information that forms the basis for parts of this news release was reviewed and approved by Robert Cinits (P.Geo.), a Qualified Person as defined by National Instrument 43-101. For further information on the Entrée/Oyu Tolgoi JV Property, see the Company’s Technical Report, titled “Entrée/Oyu Tolgoi Joint Venture Project, Mongolia, NI 43-101 Technical Report”, with an effective date of October 8, 2021, available on the Company’s website at www.EntreeResourcesLtd.com, and on SEDAR+ at www.sedarplus.ca.

ABOUT ENTRÉE RESOURCES LTD.

Entrée Resources Ltd. is a well-funded Canadian mining company with a unique carried joint venture interest on a significant portion of one of the world’s largest copper-gold projects – the Oyu Tolgoi project in Mongolia. The Oyu Tolgoi project includes two separate land holdings: the Oyu Tolgoi mining licence, which is held by Entrée’s joint venture partner OTLLC and the Entrée/Oyu Tolgoi JV Property, which is a partnership between Entrée and OTLLC. Rio Tinto owns 66% of OTLLC and is the manager of operations at Oyu Tolgoi. Entrée has a 20% or 30% carried participating interest in the Entrée/Oyu Tolgoi JV, depending on the depth of mineralization. Horizon Copper Corp. and Rio Tinto are major shareholders of Entrée, beneficially holding approximately 24% and 16% of the shares of the Company, respectively.