The Honduran international left Premier League club Wigan Athletic earlier this summer and has now joined the Rapids for whom he will be eligible to play once he receives his P-1 work visa and International Transfer Certificate.
Rapids technical director Paul Bravo was overjoyed to announce the signing of Thomas who has made close to 40 appearances for Honduras including game time at the 2010 World Cup and 2008 Olympics.
"Hendry Thomas is a player with a vast amount of experience for somebody just 27 years old," said Bravo.
"He's been playing at the highest level and in the biggest international tournaments for his country, and will be a great addition to our squad."
Rapids head coach Oscar Pareja added: "Adding Hendry to our group gives us an important player on the field who brings a lot of experience.
"He's a powerful midfielder who can break up attacks and can help solidify the center of the field for us. We are very excited to have him here."