Financial Close on Sea Lion Project

Unless otherwise defined, capitalised terms in this announcement have the meaning ascribed to them in the Definitions section set out in the Company's announcement released on 31 July 2025.

Rockhopper Exploration plc

("Rockhopper" or the "Company")

Financial Close on Sea Lion Project

Completion of Placing and Launch of Open Offer

Rockhopper Exploration plc (AIM: RKH), the oil and gas company with key interests in the North Falkland Basin, is pleased to announce that further to the announcement made on 10 December 2025 regarding the Company taking the Final Investment Decision ("FID") on the Sea Lion Project, Financial Close has now occurred.

Accordingly, the Placing, as announced on 31 July 2025, will proceed to completion and the Company will proceed to launch the Open Offer.

All key contracts in connection with Phase 1 of the Sea Lion Project have now been negotiated and entered into by the operator Navitas Petroleum and Development Limited ("Navitas"). The budgeted costs from FID to project completion, including appropriate schedule and capex contingencies and financing costs, remain at US$2.1 billion as announced in July 2025. On this basis, taking into account the proceeds of the Placing, the Company is fully funded for its equity portion of Phase 1 of the Sea Lion Project.

Sam Moody, Chief Executive Officer of Rockhopper Exploration, commented:

"I am delighted that we have reached Financial Close on the Sea Lion Project, arguably the single most important day in our history since we made the Sea Lion discovery. We now look forward to entering the development phase for the field with our partner and operator, Navitas, who have done an exceptional job both re-engineering the development and leading the financing. I am also very pleased that as a result of reaching Financial Close we are able to complete the Placing and also launch the Open Offer, where qualifying Shareholders can purchase Ordinary Shares at the Placing price. This is a very exciting time for Rockhopper and I would like to thank our Shareholders for their support and all at both Navitas and FIG for their work as we enter the next phase of the Company's history."

The Placing

As a result of FID being taken and Financial Close having been achieved, the Placing will now proceed to completion. The Placing has raised aggregate gross proceeds of approximately US$142 million from the issue of 201,102,976 new ordinary shares in the Company (the "New Ordinary Shares") at an Issue Price of 53 pence[1] per New Ordinary Share, comprising in aggregate 198,207,354 Placing Shares and 2,895,622 Interest Shares. Application has been made to the London Stock Exchange for the New Ordinary Shares to be admitted to trading on AIM and admission is expected to become effective on or around 8.00 a.m. on 31 December 2025 ("Admission"). The gross proceeds of the Placing, which are currently held in an Escrow Account, will be released to the Company on Admission.

Pursuant to the Placing, the Company will also issue a total of 50,275,732 Underwriting Warrants upon Admission. Each Underwriting Warrant will give the holder the right to subscribe for one new Ordinary Share at a Strike Price of 80 pence[2] per Ordinary Share at any time up to (and including) 5.00 p.m. on the fourth anniversary of Admission. The Underwriting Warrants will not be admitted to trading on AIM or on any other stock exchange. It is currently intended that settlement of the Underwriting Warrants via CREST will be on the same timetable as settlement of the Placing Shares and Interest Shares.

Any interest accrued for the benefit of Placees in the Escrow Account that has not been converted into the Interest Shares will be returned to Placees within 30 Business Days of Admission.

Total Voting Rights

The Company confirms that, upon Admission of the New Ordinary Shares to be issued pursuant to the Placing, which is expected to occur on or around 31 December 2025, the issued ordinary share capital of the Company will consist of 847,316,741 Ordinary Shares of 1 pence each in the capital of the Company and there will be no Ordinary Shares held in treasury. This issued share capital figure can be used by Shareholders as the denominator for the calculations by which they will determine if they are required to notify their interest in, or a change to their interest in, the Company under the FCA's Disclosure Guidance and Transparency Rules.

The Open Offer

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The Company considers it important that Shareholders who were not able to take part in the Placing have an opportunity to subscribe for new Ordinary Shares at the Issue Price. The Company is therefore providing existing holders of Ordinary Shares as at 6.00 p.m. on 19 December 2025 (being the "Open Offer Record Time") ("Qualifying Shareholders") with the opportunity to subscribe for up to 13,188,036 Open Offer Shares at the Issue Price pursuant to the Open Offer, to raise up to approximately £7 million if fully taken-up.

Subject to the fulfilment of certain conditions, the Open Offer will provide Qualifying Shareholders with the opportunity to apply to acquire Ordinary Shares (the "Open Offer Shares") at the Issue Price pro rata to their holdings of Existing Ordinary Shares against all Existing Ordinary Shares held by Qualifying Shareholders as at the Open Offer Record Time on the following basis:

1 Open Offer Share for every 49 Existing Ordinary Shares held by Qualifying Shareholders

(the "Open Offer Entitlement")

Entitlements to apply to acquire Open Offer Shares will be rounded down to the nearest whole number and any fractional entitlements to Open Offer Shares will be disregarded in calculating an Open Offer Entitlement and will be aggregated and made available to Qualifying Shareholders pursuant to an excess application facility.

The Open Offer is structured to allow Qualifying Shareholders to subscribe for Open Offer Shares at the Issue Price pro rata to their holdings of Existing Ordinary Shares against all Existing Ordinary Shares held by Qualifying Shareholders. Qualifying Shareholders may also make applications in excess of their pro rata initial entitlement up to an amount equal to the total number of Open Offer Shares available under the Open Offer less an amount equal to such Qualifying Shareholder's Open Offer Entitlement. To the extent that pro rata entitlements to Open Offer Shares are not subscribed for by Qualifying Shareholders, such Open Offer Shares will be available to satisfy such excess applications. Applications under the excess application facility may be allocated in such manner as the Directors may determine, in their absolute discretion, and no assurance can be given that any applications under the excess application facility by Qualifying Shareholders will be met in full or in part or at all. Applications made under the excess application facility will be scaled back at the Directors' discretion if applications are received from Qualifying Shareholders for more than the number of Open Offer Shares available under the excess application facility.

The Circular containing further details of the Open Offer, together with an Open Offer Application Form for Qualifying Shareholders who hold their Ordinary Shares in certificated form, is expected to be posted to Shareholders on 29 December 2025. Details of the expected Open Offer timeline are included below.

EXPECTED TIMETABLE OF PRINCIPAL EVENTS REGARDING THE PLACING AND OPEN OFFER