SkyTeam airlines Air France–KLM offer a good solution for travelers from the United Kingdom planning to visit Sint Maarten also in the main tourist season. Return flights from Birmingham, Manchester, Edinburgh, Newcastle, Leeds, or London to St. Maarten are available from £398 incl. all taxes and fees, onboard meals, and handbags. Checked luggage is available for an additional fee.
Flying From: Birmingham, Manchester, London, Newcastle, Edinburgh, Southampton
Flying To: Sint Maarten
Airlines: Air France and KLM
Luggage: Hand luggage only
Travel Period: January to June or in September 2022
Max stay: 3 months
Book by: 26th of September
Booking sample of cheap Air France-KLM flights from the UK to Sint Maarten from £398. As per the above link, you would fly from Southampton to this Caribbean island on the 9th of May. Inbound from St. Maarten back to the United Kingdom on the 22nd of May 2022.