Beccie and her dad, Rob, started their climb at 8am. They were back at the foot of the mountain at around 6.30pm.
"I wasn't thinking about the climb in the run-up to it. We just had to get it over and done with," said Beccie.
"The first bit of the climb was through a place called the Forest Of Shadows. There were great views from there - we could see the top of Mount Olympus.
"The best place was the Plateau Of Muses, where you could see faces carved into the rock.
"I did feel a bit tired at the end, but happy as well. I was doing it for Team GB and it was an amazing experience."
Beccie intends to take a break before dreaming up her next expedition, but she'll be spending the coming days supporting Team GB, especially in her fave events - the swimming and diving.