The comedian, who plays Long John Silver in the Sky1 drama, said that the entire team struggled to cope with the extreme conditions they experienced while shooting.
"We filmed it in Dublin this time last year. It was absolutely freezing and snow was coming down," he told The Sun. "Then we went over to Puerto Rico which was lots of winter sun.
"We had been freezing, then we went there and just moaned about being too hot. The humidity there was unbelievable. And trying to have a sword fight on soft sand is very hard."
Izzard recently told Digital Spy that he was pleased the new Treasure Island had snubbed the "clichéd" representation of pirates.
"I agreed to do it because it is a Goodfellas-style kick-ass version," he said. "We want to keep everyone watching it, but we also want to add a real edge to it."
Treasure Island airs New Year's Day and January 2 at 7pm on Sky1.
Watch Digital Spy chat Treasure Island with Eddie Izzard below: