Waves as high as 18ft ripped across the east coast of the island.
The capital of Colombo was hit by flash floods but the provinces of Muttur and Trincomalee were among the worst hit.
At least one million people had to flee their homes and head for high ground.
More than 1,000 miles of south east India was battered by waves as high as 12ft.
The state of Tamil Nadu, and its capital Madras, were the worst-affected, but the Andhra Pradesh province and tourist area of Kerala were also hit.
Waves as high as coconut trees washed away hundreds of small fishing boats.
Cars and household debris littered the sea. Locals and visitors fled to the hills as the wall of water crashed on to the west coast of southern Thailand.
The northern tip of Sumatra island suffered the full force of the waves, generated by the huge earthquake just 65 miles off its coast.
Flash floods covered a countryside and left entire communities cut off.
Waves struck villages scattered along the northwest coast. Many victims had been swimming or riding on jet skis. Tens of thousands of people were evacuated from high-rise hotels and apartments.
The quake sent 4ft high waves crashing on to the low-lying capital of Male. Much of the city was left underwater and the airport was forced to close but later reopened. Many of the country's 200 islands remained out of contact.
Huge waves slammed into the southern port of Chittagong and caused widespread flooding in at least 30 districts.
Countries including Kenya, Tanzania and Somalia were further away from the quake, but people were still killed by waves.
Thousands of people have been forced out of their homes, and there are worries about fishermen hit by the disaster.
The worst affcted area is reported to be the Irrawaddy Delta, where 17 villages were hit and 200 people left homeless.
It's not definitely known how many people died, as the Burmese government are very secretive.
One person died, but there has been a great deal of flooding on the islands.