Be aware that international roaming can be expensive, especially in Seychelles because of its remoteness.
With a local SIM card, like a Seychellois one, you can enjoy local rates, which are almost always lower than international roaming rates.
The most advantageous solution is to acquire the SIM card offered during the digital boarding pass application for Seychelles.
In August 2023, it was available for 45 € with 50 GB, which is the most advantageous offer.
You can buy also a SIM card from one of the local mobile operators.
You can get a Seychellois SIM card for 100 SCR (7 €) in Airtel and Cable & Wireless stores across Seychelles.
A bundle featuring 1 GB of data is available for as low as 200 SCR (14 €).
You can get a Seychellois SIM card in the official stores of Airtel and Cable & Wireless
They are also available at Victoria/Seychelles International Airport.