What does “dip your toes in the water” mean?

In this news report, families are “eager to dip their toes” in a river — real toes, real water. But dip your toes in (the water) is more useful as an idiom: to try something new slowly and carefully, before you decide to do it fully. You test the water first. You can dip your toes into a new hobby, a new job, or a new language.

The idiom dates from around the 1950s and keeps the swimming picture: you check the temperature before you jump. It often takes into: “She dipped her toes into investing before buying more.” The clip gives the idiom a serious echo — it is about swimmers who went in without testing anything, and the calm-looking river turned dangerous within seconds.