Cover your legs and shoulders, and take off shoes and hats if you are entering a Buddhist temple.
The mistreatment of Buddhist images and artefacts is a serious offence and tourists have been convicted for this.
Only months after winning Sri Lanka's brutal civil war, President Mahinda Rajapaksa is locked in a bitter election contest against the former army chief.
Mr Rajapaksa, a war hero among the Sinhalese majority, is ironically competing for Tamil votes – and dividing Sinhalese loyalties – vying against retired Gen Sarath Fonseka, who led the army to victory and was a surprise candidate.
Don’t take photographs of military bases, government buildings or vehicles used by VIPs (this includes numerous sites in central Colombo).
You can be fined if you ignore instructions not to smoke or drink in certain public areas.
Alcohol and meat are not usually available on religious holidays.