Additional Listing

Inmarsat plc (the 'Company')

24 May 2018

Additional Listing

The Company confirms the allotment and issue of 3,015,936 ordinary shares of €0.0005 each ('Shares') at a price of 367.64 pence per Share, to shareholders who are participants in the Company's Scrip Dividend Scheme (the 'Scheme') in respect of the final dividend for the year ended 31 December 2017 payable on 25 May 2018. This represents approximately 0.66 per cent of the current issued share capital of the Company. The Shares rank equally with existing issued ordinary shares.

Applications have been made to the Financial Conduct Authority for the Shares to be admitted to the Official List, and to the London Stock Exchange for the Shares to be admitted to trading. Dealings in the Shares are expected to commence on 29 May 2018. Following admission, the issued capital of the Company will comprise 461,572,769 Shares.

The figure of 461,572,769 may be used from 29 May 2018 by shareholders (and others with notification obligations) 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 Disclosure and Transparency Rules.

The Scheme Terms and Conditions and Mandate Form are available on the Company's website at www.inmarsat.com in the Investors' section. Further queries on the Scheme should be directed to the Company's Registrar, Equiniti, on 0371 384 2268 (from the UK) or +44 121 415 7173 (from outside the UK).

In accordance with Listing Rule 9.6.1, copies of the following documents relating to the Scheme were submitted to the National Storage Mechanism and are available for inspection at http://www.morningstar.co.uk/uk/NSM:

· Terms and Conditions

· Mandate Form

Alison Horrocks

Company Secretary