Best time to travel to Sri Lanka is between the main rainy seasons. The period from November to April is the driest season on the south west coast and up in the hills. Here, some of the best beaches and many other places of tourist interest are located. Therefore, period between November and April is the best time to visit this region and this period is also considered as tourist season in Srilanka. May to September is the best time to visit east coast, as it is dry during this period.
The cheapest option is based on 5* airline Qatar Airways. Their promotional offer allows to book return flights in travel period between 15th of April and 22nd of June 2015. (Based on latest date of departure to Colombo). This promotion is valid for bookings made till 8th of March 2015 or until sold out.
Accommodation - compare hotel rooms in Sri lanka already from €11.
Booking sample
Qatar Airways
Euerope (Switzerland/Scandinavia/Brussels etc.) - Sri Lanka from €403 (booking directly with Qatar Airways)
Geneva - Colombo from €393
Oslo/Stockholm - Colombo from €408
Turkish Airlines
Brussels - Colombo for €422 (+€22 booking fee)
London - Colombo from £382
Etihad Airways
Germany (Munich) - Colombo for €465
Kuwait Airways
Rome/Italy - Colombo from €396
Plenty of low-cost airlines are connecting these European airports. We recommend to use service of Skyscanner to quickly find out which low-cost airline offers the most competitive fare from your home town.
Booking sample of a roundtrip flight to Sri Lanka from Europe for €393 here. In this case you would be leaving from Geneva to Colombo on 11th of May and returning back to Europe from Asia on 25th of May 2015.