So I was looking at the route on ZeldaSpeedruns for the glitchless category, and noticed how not helpful the GBT part of it was. I've managed to get longjumps to most of the 'red keys' but the last one, in the lower tunnel, I can't seem to get to without getting ice arrows... so how would I do that?

I have since found my problem to be that he dives when doing the longjump, which stops him from being able to grab the ledge. However, I don't know how to stop this...

I know which route you are talking about and that is old, longjumps are now banned from glitchless. However to skip gekko fight, you can still perform a precise jump on the edge of the ice arrow block as zora. Unfortunately since longjumps are banned and getting into ikana canyon without them is impossible, ice arrows are now a reqiurement for glitchless.

Ice arrow block? Just to be clear, I'm in the room where you have to freeze the octoroks. And thanks for the route tip, Ag :)