The ambitious expansion comes amid a post-war revival that has pushed up hotel room rates and given the hospitality industry something to cheer for the first time in years.
For once, after seeing tourists put off by violence and travel warnings from foreign governments, the industry says it is struggling to find places for the visitors, most of whom come from Britain, Germany, France, India and Japan.
"Hotels are overbooked, a 'problem' which our hotels have not experienced for a very long time," said Srilal Miththapala, who heads the Tourist Hotels Association of Sri Lanka.
Counting on this solid demand, many are now investing in new furniture, bars, restaurants, swimming pools and extensions.
Sri Lanka's tourist board expects the total number of hotel rooms to grow