Far enough away to avoid chlorine or salt water splash.

as far as possible id say as ageneral rule .

I take it we are talking edible figs here, rather than Ficus benjamina. If so, read on.....We recently asked our surveyor if he thought our big fig tree, planted very close to the house would be damaging the foundations, and he said that generally speaking, fig trees tend to have a single tap root which goes down deeply, searching for water, rather than being shallow rooted and extending widely, so a swimming pool structure shouldn't be compromised. However, fig leaves are very large and make a lot of mess in autumn, and you don't want your pool full of those, so my advice would be the same as Nosey's or Bamboo's, but maybe for different reasons - as far away as possible.
I've just thought of a different reason - almost year round you get the secondary, inedible figs falling off the tree. They are a nuisance and stain and make a mess of our lawn and paving stones. It'd be even worse if they fell into the water. If the tree is high and it isn't possible to harvest all the fruit, it starts to ferment and can attract large numbers of wasps. When this awful, smelly mess falls, you don't want to be under it. We always have to move our washing line in high summer!

Ctrtcr, if you are talking about planting in Barbados, I would plant them as far away as possible! With a very few exceptions, such as F. lyrata, ficus trees have massive, invasive, surface roots, that are likely to break pool sides and decking. They should be given an are at least one and a half times as wide as it is likely to grow. For instance, Ficus microcarpa, the most commonly planted species here in Phoenix, would normally grow to 50 feet wide, if unchecked. So, they should be planted at least 37.5 feet from the nearest pool decking.