Top ranked Eithad Airways offers some great option not only for travellers in Switzerland to visit beautiful Thai island Koh Samui out of main tourist season. If you are flexible you can book return tickets in May already for €399 when departing from Geneva. Adding approx €40 you can also fly between September and November. (Note that October and November should be the rainiest months though).
As mentioned this Etihad Airways promotion is available when travelling to Koh Samui in May and June then September to end of November 2017. Based on date of your outbound flight from Europe to Thailand. Max stay 1 month. Promo sale is running till 12th of May or until the cheapest tariff is sold out. Also consider great option from Europe to Thailand on another 5-star carrier Qatar Airways. Return flights to Krabi are now available already for €355 throughout next whole peak season 2017/2018. You can refer to both deals below.
Booking sample
Geneva - Koh Samui for €454 (Directly with carrier you can compare all available travel dates there)
Need an afforeable accommodation in Koh Samui we recommed service of Booking.com or consider following promo code that offers Hotels.com or Amoma.
Booking sample of latest prmotional deals with 5* Etihad Airways flights from Geneva to beautiful Koh Samui, Thailand for €399 here. Also as per our booking sample you would depart from Switzerland to this Thai isle on 28th of May. Your return flight from South East Asia back to Europe would be on Thursday, 15th of June 2017.