Add water, vinegar, salt, sugar, Mexican oregano, and bay leaves to a medium saucepan and bring to a boil.

Slice radishes into thin circles. Slice one red onion into thin slivers.

Once your mixture is boiling, add sliced veggies to the pot.

If you like crunchy pickles, remove from heat immediately. If you like your pickles slightly softened, allow to boil for about 2 minutes, then remove from heat.

Pour all contents of pot into a heat-safe container and allow to cool on counter to room temperate. Cover and refrigerate