The two men walked out of Bangkok Remand Prison at 5.30pm on Friday (Apr 23).
Lawyer Norasate Nanongtoom said the court had allowed his clients bail on condition they do not leave the country or take part in political activities deemed threatening to the monarchy, reports the Bangkok Post.
They each posted B200,000 as surety. Both men had previously been refused several requests to be released on bail to prepare their court defence.
Mr Somyot had been behind bars for 74 days and Mr Jatupat for 47 days, supporters said.
The two face charges, including lese majeste linked, to the two-day rally at Sanam Luang on Sept 19-20 last year. Altogether 22 protest leaders were charged in relation to the political protest. Most remain locked up. Some have dismissed their lawyers as a protest against a legal system that they say is tilted against them.
One other activist, Patiwat Saraiyaem, was finally granted bail by the court on April 9. Mr Patiwat is better known as Morlum Bank and is an Isan folk singer.
Small groups of people continue to stage regular silent protests calling for all of the detained political activists to be freed.
At least 88 activists have been charged under Article 112 of the Criminal Code, the lese majeste law, since its use was revived in November, according to Thai Lawyers for Human Rights.
Conviction under the royal defamation law carries a jail term of up to 15 years. Some activists face multiple charges that could result in consecutive sentences lasting for decades.