Let's not forget that every time Sims wade into water, they have to change into their swimsuit...and if you have mermaids, they change into their mermaid outfit after changing into their swimsuit.

Seriously. I had kids swimming to school once before I built a school on the island most of the families with kids were actually living in.

I suspect one of the reasons I don't have too much lag is because I downloaded Lea.Sikora's emptied version (with just the ports and diving spots), then rebuilt the town of my own accord by adding in my own lots and Sims. That said, I highly recommend installing NRaas Go Here and putting up a network of LLAMAs if you have Supernatural (I put mine in a bunch of ports, plus in lots that were close to a lot of rabbit holes or busy community lots). I CASted them funky colors so that they'd fit in better with Isla Paradiso's aesthetic.

I never had a sim swim to school, they all simply teleported away to a more suitable place to then take whatever ride they needed. I never either experienced mega lag or other issues playing IP and reading you all now, I am wondering why.