The tsunami waves struck at night without any warning, destroying hundreds of buildings.
Officials say the tsunami could have been caused by undersea landslides after Anak Krakatau volcano erupted.
The Sunda Strait, between the islands of Java and Sumatra, connects the Java Sea to the Indian Ocean.
The disaster management agency has warned people to stay away from the coastline due to fears of another tsunami.
Saturday’s tsunami struck at about 21:30 local time (14:30GMT), during a local holiday.
It hit several popular tourist destinations including the Tanjung Lesung beach resort in the west of Java island.
Footage shared on social media showed a large wave crashing into a tent in the resort, in which a popular Indonesian rock band, Seventeen, was performing. Members of the band were seen being swept away as the wave destroyed the stage.
In a tearful Instagram video, singer Riefian Fajarsyah, said the band’s bassist and road manager had died, and that three other band members and his own wife were missing.
A crew member, Zack, said on Instagram that he survived by grabbing onto part of the stage, and “in the final seconds [underwater] I almost ran out of breath”, Reuters reported.
Red Cross official Kathy Mueller told the BBC: “There is debris littering the ground, crushed cars, crushed motorcycles, we’re seeing buildings that are collapsed.”
It appears that the main road into Pandeglang has been badly damaged, making it difficult for rescuers to reach the area, she added.
Eyewitness Asep Perangkat said “cars were dragged about 10 metres, and so were containers.”
“Buildings on the edge of [Carita] beach were destroyed, trees and electricity poles fell to the ground,” he told AFP news agency.
Officials say more than 160 people were killed in Pandeglang – a popular tourist district on Java known for its beaches and national park.
Meanwhile, 48 were reported dead in South Lampung on Sumatra, and deaths were also reported in Serang district and Tanggamus on Sumatra. Officials fear the death toll could rise further. (Courtesy BBC)