Ex-military family, and familiar with school in Germany (but it's been quite some time). Your best bet is your base, and connections through your base and other families there. I can tell you that German high school does usually not do any sports or extracurriculars (other than plain PE), only pure academics. Sports are all happening out of school, in various clubs. You may find a swim team on your base with other military kids, or a club in your town.

18:29 here. Found the swim league, it’s EFSL. (European Forces Swim League)

We have friends that moved to Germany and their kids swim in whatever league it is for the military bases. It’s definitely possible. And the swim meets are all over so it’s quite fun to travel around Germany and even to other countries.

Which base/city are you going to?

Are you on base? If so, some bases have teams and I believe there's a league of sorts (or there was). If not, then start with the German Swimming Federation's website (Google translate will help enough to where you should be able to navigate) and there should be a list of LSCs (like PVS). Their website will often have a club listing page.

I was able to find Weisbaden's team. Maybe from there, you can find the club for where you will be stationed in Germany.

http://www.wiesbadenwahoos.com/

The only help I can give you is that it does exist. I know of a military family stationed in Italy that continued swimming. They had meets in other countries. One of the kids went on to swim in college.

Military family and moving to Germany. We club swim for Mako currently and a quick google doesn't give me anything for swim. High school appears to be an option but we are looking for year round. Any experience?