$25M+ Strategic JV Agreement with Endeavour Mining

East Star Resources Plc (LSE: EST), the Kazakhstan-focused gold and base metals explorer, is pleased to announce that it has entered into a binding Earn-In and Joint Venture Agreement (the "Agreement") with Endeavour Exploration Limited ("Endeavour"), a subsidiary of Endeavour Mining PLC (LSE: EDV/TSX: EDV), one of the world's leading gold producers.

Key Terms of the Agreement

• The Agreement establishes a joint venture between East Star and Endeavour for the exploration and development of gold projects in Kazakhstan.
• Endeavour has the right, to earn up to an 80% interest in a newly incorporated joint venture company ("JVCO") through staged investments:

o Stage 1: Endeavour to invest US$5 million within two years to earn a 51% interest in JVCO;

o Stage 2: Endeavour to invest an additional US$20 million over three years to increase its interest to 70%; and

o Stage 3: Endeavour to fund and complete a NI 43-101 compliant Pre-Feasibility Study ("PFS") to earn a further 10%, bringing its total interest to 80%.

• East Star will retain a 20% interest in JVCO upon full earn-in by Endeavour.
• East Star will act as Manager of the Joint Venture during the initial phase and receive remuneration for this role.
• Endeavour will make milestone payments to East Star during the earn-in period, subject to review by an independent Qualified Person, based on pre-agreed amounts per ounce for any Maiden Resource and any maiden PFS.
• Following the earn-in period, both parties will fund JVCO pro-rata to their respective shareholdings, with dilution provisions in place for non-participating parties.

Alex Walker, CEO of East Star Resources, commented:

"We are delighted to sign this Agreement with Endeavour, which is a transformational milestone for East Star that validates the quality of our exploration programme and provides a clear pathway to unlock the full potential of our gold exploration strategy.

Endeavour is a top 10 global gold producer, with one of the best discovery track records in the sector and, importantly, they have an excellent track record of converting those discoveries into mines, having built five projects in the last 11 years, all to plan, across three jurisdictions. As a result, Endeavour is a world class partner for East Star and we look forward to delivering value together, for all of our stakeholders."

Figure 1: Areas of Interest subject to the Agreement. Two proven, underexplored mineral belts

Notice of Investor Webinar

East Star will host a webcast and Q&A for investors to discuss the $25M+ strategic JV agreement with Endeavour Mining for gold exploration in Kazakhstan via the Investor Meet Company platform on Tuesday, 18 November 2025 at 10 a.m. GMT. A recording of the webcast, along with the accompanying slides, will be made available on the Company's website later that day.

Investors can sign up to Investor Meet Company for free and add East Star Resources plc in order to attend the webcast via: https://www.investormeetcompany.com/east-star-resources-plc/register-investor.

Investors who already follow East Star Resources plc on the Investor Meet Company platform will automatically be invited. Questions can be submitted pre-event via the Investor Meet Company dashboard up until 9 a.m. GMT on 17 November 2025, or at any time during the live presentation. No material new financial or other information will be provided.

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About Endeavour Mining PLC

The person who arranged for the release of this announcement was Alex Walker, CEO of the Company.