Nothing preparation is needed providing you stay within Apple's approved getting wet limits. Avoid: soap and hot water (shower is not recommended for watches), high pressure water jets, or diving below approved depth.
There is nothing that needs doing before getting the Watch wet. Water in the speaker, however, can cause a reduced volume of sound on the Watch. To correct this if it happens I suggest though that you learn to use the water ejection function so you know how to use it after the Watch gets wet. When your Watch is on your wrist slide up on the screen and look for the water droplet function. Tapping that create a sound wave that ejects after from the speaker.
Do we have to do anything with apple watch 3 before getting it wet?
