BBC website:
Here in Kata Beach on the coastal roads a big mess, with motorbikes, lanterns, roofs etc floating around. There were lots of people on the beach this morning, I have seen two bodies myself, plus quite some people are still missing.
The damage is considerable, some of the major hotels here are flooded. Patong Beach, the main tourist destination on Phuket, has been hit a lot harder, more than half the town has been flooded.
Steven van Leeuwarden, Phuket
Suddenly I felt a dizziness in my head and I was feeling the shake of the land.
My parents immediately responded and every one of us shot out of the home.
Since it was Sunday the people were still sleeping unknown of the quake.
We immediately shouted and asked everyone to get out.
Our house was 1km exactly from the shore in span of no minutes the sea water was flooding inside our places, and around 8:50am it was waist high.
We asked everyone to lock the doors and go to higher levels.
We left the place immediately by 9:30am when the neck-level water started draining.
K S Saran, Saravanan, Chennai
I live on the 25th floor of a seemingly well constructed 31 floor building, next to the British embassy.
But the shaking was tremendous.
All staff ran out immediately of the building
My first thought was, that someone came into my room, because I heard some noise, sounded like somebody broke into my room.
Then I thought I was dreaming, because the floor was moving.
Then I started to realise what was going on and stepped outside my door to see what other residents were doing.
I saw nobody. Normally the housekeeping staff would be cleaning and I thought I heard them screaming and leaving the building.
I told my girlfriend to get dressed and we ran down the stairs, all 25 floors.
Marcel Emmeneger, Bangkok
We were anchored in Patong beach [Thailand], where the beach area basically drained of water, then after five minutes the water filled back in and large waves approximately 8m high crashed onto the main road in Patong.
Small boats dragged anchors. The beaches along the west side of Phuket were basically washed away.
All boats are standing by for more after reports of a quake in the Nicobar islands.
Mike Ryniker, Phuket
A friend of mine, who is on holiday with her husband and children in Phuket, called and said that there was a disaster. Their hotel was ruined and they are now standing on a mountain, waiting for the next wave, terrified.
Victoria, Sweden
It's terrible. The rain and the wall of water and the horrific shaking. In so many years of living here I have not ever seen anything as terrible as this. God is angry. God is telling us he is angry.
Kareemoff Sumyun Gy, Jakarta
I live in Ao-Nang Krabi [Thailand]. The scene is quite bad here - with upturned boats lying broken and strewn across the street. Many tourists and locals are missing - they were leaving on tours as the wave hit. Army and police are arriving in their masses.
Rob Bysouth, Krabi, Thailand
The whole of Male and all islands are under knee-deep water after huge waves washed the islands.
Mohamed latheef, Male', Maldives
This morning my brother called me to say that he is alive. He lives on the small tourist island, Koh Phi Phi near Phuket in south Thailand. He reported that: "The whole island is smashed, there are dead people all over!" He was trying to find his Thai girlfriend and a Danish friend.
Stinus, Copenhagen, Denmark
People living in the costal areas have been struck by panic. Huge tidal waves hit the coast. Rescue efforts are under way. Exact damages are largely unknown.
Sriram Srinivasan, Chennai, India
Waves never seen before hit the island of Penang, Malaysia, devastating coastal areas. Waves of more than 10ft high swept away wooden stilt houses at coastal areas. Ambulances are seen rushing to affected areas.
Victor Tan, Penang, Malaysia