Turn your smartphone off immediately when you notice it has taken a dip. Remove any screen protector or case you have on, to get rid of excess water.
The next step is to ensure that the phone is completely dry on the outside. To do this, use a clean and absorbent cloth to wipe the phone thoroughly, leaving no water behind.
After wiping the phone dry completely, remove the SIM card tray and take out your SIM and microSD card if you use one. This will protect the SIM and memory card from getting damaged.
Put the phone in a vacuum bag to draw all excess water from the smartphone. To do this put the phone in a ziplock bag, close it with enough space for a straw and suck the air out.
Once you have done previous steps to get rid of water, there might still be moisture inside. To get rid of the moisture, put it in uncooked rice for 48 hours or at least overnight.
Don’t charge your phone until it’s fully dry. While the impulse to plug it in to check whether its working is strong, resist it as it will only spread the water inside.
A hairdryer might seem to be the best bet to dry your phone quickly but it’s not. On the contrary, it might push the water further inside, damage the internals, and melt the wiring.
Also, fight the urge to shake the water out of the smartphone. While some water might come out, a lot of it will get further inside because of shaking and damage internal parts.