Richards, 28, joins the Whitecaps after making 147 appearances over six seasons in New York, scoring 21 goals and 26 assists in that span. The Red Bulls acquired the Clemson University product in the second round, 19th overall, in the 2007 MLS draft.
"Richards is a speedy player and very dangerous down the wing," said Whitecaps head coach Martin Rennie in a statement. "He brings plenty of MLS and international experience to our club, so we’re delighted to have him in Vancouver."
Richards, who scored eight goals in 37 appearances for Jamaica, will be available for Vancouver's game at Chicago Fire on Saturday.
Le Toux leaves Vancouver after four goals and one assist in 19 appearances with the club.