The 26-year-old, who has previously been on the books of Manchester City, is widely regarded as one of the best players in his home nation.
The forward has been the leading scorer for Muangthong United in each of their last three seasons in the Thai Premier League, but has now sought pastures new in Spain.
"I have a great opportunity, which is to play in the best league in the world and I'll be trying to make the most of it. I'll give everything I've got for Almeria, to win the affection of their fans and I'm very excited," he told reporters at a press conference.
Dangda previously had a trial with Atletico Madrid.