You will need a visa to enter Sri Lanka. You can get a short stay visa online at: Electronic Travel Authority (ETA ). Although it is still possible to get a tourist visa on arrival, it is recommended that you do this before you travel. If you arrive in Sri Lanka without a visa, you could face delays. For the most up-to-date advice on visas check with the Sri Lankan High Commission in the UK. If you experience any difficulty with the ETA System, or if you are travelling for paid or unpaid work, you should get a visa from the Sri Lankan High Commission before you travel.
Your passport should be valid for a minimum period of 6 months from the date of entry to Sri Lanka.
UK Emergency Travel Documents
UK Emergency Travel Documents are accepted for entry, airside transit and exit from Sri Lanka.