Odds of Hanging On
If you're well-liked and have a job working as a swim instructor, odds are your job will still be there for you when the season or session starts up again.
If you spend more time chatting up the other teachers than looking over and teaching your class, you probably won't be invited back next year.
Bottom line: If you're a decent instructor who cares about what you're doing and shows up, you'll have a job.