To arrive in Sri Lanka, one needs to have a passport that doesn't expire for a minimum period of six months from the date you land in the country. Apart from a valid visa, you must also make certain that you have an ETA, or Electronic Travel Authorisation, which is issued by the "Sri Lanka Overseas Missions and the Visa Section" of the Department of Immigration and Emigration in Colombo. Nonetheless, if you're someone from the Maldives, Seychelles, or Singapore, you aren't bound by this requirement. Initially, the ETA is granted for a period of one month, which can be increased up to six months if the need arises. Also, do make sure that you have copies of your travel documents safely stashed somewhere in your suitcase, in case something is to happen to the originals.