The decision Wednesday means the 23-member Iroquois team will miss the Lacrosse World Championships in Manchester.
A British Consulate spokeswoman said the team would be able to travel only with documents the United Kingdom considers valid.
Tonya Gonnella Frichner, a member of the Onondaga Nation who works with the team, said it was told by British officials that members would have to use American or Canadian passports in order to travel to Britain.
The decision was announced hours after the U.S. cleared the team for travel on a one-time waiver at the behest of Secretary of State Hillary Rodham Clinton. Nine team members are Canadian-born and still needed Canadian waivers before Britain announced its decision Wednesday afternoon.
The players regard U.S. government-issued documents as an attack on their identity, but U.S. officials have said their Iroquois documents did not meet new, stricter passport standards.
Mrs. Clinton determined that the team members born within U.S. borders did not need U.S. passports to make the trip and granted the players a “one-time-only waiver” to travel on their Iroquois passports, said State Department spokesman P.J. Crowley.
Asked why the department had dropped its opposition, he said, “There was flexibility there to grant this kind of one-time waiver given the unique circumstances of this particular trip.”
U.S. Rep. Louise M. Slaughter, New York Democrat, said earlier Wednesday that she was happy that the team was cleared by the State Department to go to the games.
“I am relieved that this bureaucratic technicality has been papered over and these young men can go and do what they have trained to do: Play lacrosse and compete on the international scene,” she said.
The British government said previously it would give the players visas only if they could guarantee they would be allowed to go home.
A message left at the Canadian Consulate on Wednesday wasn’t returned.
The Iroquois Confederacy oversees land that stretches from upstate New York into Ontario, Canada.
The Iroquois, known to members as the Haudenosaunee, helped invent lacrosse, perhaps as early as 1,000 years ago. Their participation in the quadrennial world championship tournament is a rare example of international recognition of their sovereignty.