The Thai government declared a public holiday on Friday for people in the kingdom to mourn King Bhumibol Adulyadej, who died on Thursday at the age of 88.
The government also asked Thais to stop entertainment activities for a month.
The king's body is set to be moved from Siriraj Hospital to the Grand Palace on Friday, a complex of temples and pavilions in the heart of Bangkok.
Many people are expected to go to Siriraj Hospital, the Grand Palace and other places to mourn the late king, who was the world's longest-reigning monarch with 70 years of rule.
On social media, many Thais changed the color of their profiles to be black and white for their beloved king.