Non Physic Volume Based Swimming Mechanic

Hey, I’ve been thinking about having swimmable water, but i can’t really figure out an optimal solution for it. My goal is to have the swimming mechanic like other old school games like Ratchet And GTA. Once on top of the water plane, you’re only allowed to move towards the X and the Y Axis or Jump. Once you press the dive button you go under water you’re allowed to swim downwards and upwards.

Just like :

I’ve seen some Tomb Raider stuff using Unreal Engine and it has the kind of swimming mechanic i want.
In this video

Thanks :))