Gather ingredients. Start by collecting fresh radishes, vinegar, sugar, salt, and optional spices.

Slice the radishes. Wash the radishes thoroughly and slice them into thin rounds or matchsticks—about 1/8 inch thick.

Prepare the brine. In a small saucepan, combine equal parts vinegar and water with sugar and salt over medium heat. Stir until dissolved.

Combine radishes and brine. Place the sliced radishes in a clean jar and pour the warm brine over them until fully submerged.

Let cool and refrigerate. Allow the jar to cool to room temperature before sealing and refrigerating. The radishes will be ready in about 30 minutes.