The northern city, which is a four-hour flight from Rio, was one Roy Hodgson hoped to avoid playing in before the World Cup draw was made.
But it will provide the venue for England’s first game against Italy on Saturday night and in temperatures and humidity levels far greater than the squad is accustomed to.
The players have spent time in the Algarve, Miami and Rio in a bid to acclimatise themselves and have been taking malaria tablets since Tuesday.
Centre-back Cahill has so far avoided any ill-effects from the medication and feels the preparation could not have been any better.
"I don't really know what to expect," he said. "I have been told, obviously, about the humidity.
"That was the first thing we were all made aware of, but that's what we've been training for and preparing for in the last couple of weeks. That was the main thing really.
"I think we've prepared the best we possibly could in the couple of weeks we had.
"We did the hot-weather training, been in hot climates, done the heat chambers, worn extra layers of clothing.
"So we've prepared as best we possibly could. Obviously being English players we're not used to those conditions but in the three weeks that we've had we have done all we possibly can."
England will train at the Arena Amazonia on Friday after cancelling a session on Thursday in favour of training at their hotel after the four-hour flight from Rio.
Italy do not travel to Manaus until the day before the game and while they are favourites, Cahill feels England have improved since the teams met at Euro 2012, when the Azzurri won on penalties.
Cahill said: "I think a lot has changed in the couple of years since we played them [at Euro 2012].
"We are certainly a strong team and we are definitely ready for the game. I can't wait to get started and the preparation has gone fantastically well so we're just ready for the game to come along now."