The Light Phone III has a water resistance rating of IP54, which is defined as "your product can be exposed to limited amounts of dust and water splashes from all directions."
The Light Phone II has a water resistance rating of IPX3, which is defined as "your product can be exposed to spray water of up to 60 degrees without sustaining any damage."
If liquid splashes on your phone or dust gets on it, wipe it off with a soft, lint-free cloth (for example, a lens cloth) and ensure that your phone is dry and free of dust before opening the SIM tray. Minimize exposure to soap, detergent, acids or acidic foods, and any liquids—for example, salt water, soapy water, pool water, perfume, insect repellent, lotion, sunscreen, oil, adhesive remover, hair dye, and solvents.
If your phone has been exposed to liquid, unplug all cables and do not charge your device until it’s completely dry. Using accessories or charging when wet may damage your phone. Allow at least 5 hours before charging. Do not dry your phone using an external heat source or insert a foreign object into the Micro USB connector such as a cotton swab or a paper towel.