13 November 2025

East Star Resources Plc

("East Star" or the "Company")

$25M+ Strategic JV Agreement with Endeavour Mining for Gold Exploration in Kazakhstan

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.

Contacts:

East Star Resources Plc

Alex Walker, Chief Executive Officer

Tel: +44 (0)20 7390 0234 (via Vigo Consulting)

SI Capital (Corporate Broker)

Nick Emerson

Tel: +44 (0)1483 413 500

Vigo Consulting (Investor Relations)

Ben Simons / Peter Jacob / Anna Stacey

Tel: +44 (0)20 7390 0234

About East Star Resources Plc

East Star Resources is focused on the discovery and development of copper and gold in Kazakhstan. The Company is pursuing multiple exploration strategies including:

·    Volcanogenic massive sulphide (VMS) exploration, which to date includes a deposit with a maiden JORC MRE of 20.3Mt @ 1.16% copper, 1.54% zinc and 0.27% lead, in an infrastructure-rich region, amenable to a low capex development

·    Copper porphyry and epithermal gold exploration, with multiple opportunities for Tier 1 deposits

Visit our website:

www.eaststarplc.com

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About Endeavour Mining PLC

Endeavour Mining is one of the world's senior gold producers and the largest in West Africa, with operating assets across Senegal, Côte d'Ivoire and Burkina Faso and a strong portfolio of advanced development projects and exploration assets.

A member of the World Gold Council, Endeavour is committed to the principles of responsible mining and delivering meaningful value to people and society. Endeavour is admitted to listing and to trading on the London Stock Exchange and the Toronto Stock Exchange, under the symbol EDV.

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

This announcement contains inside information for the purposes of Article 7 of Regulation 2014/596/EU which is part of domestic UK law pursuant to the Market Abuse (Amendment) (EU Exit) Regulations (SI 2019/310) ("UK MAR"). Upon the publication of this announcement, this inside information (as defined in UK MAR) is now considered to be in the public domain.