There are reports of being electrocuted by a phone, but I don't know the viability of this idea. Below is what I have done on multiple occasions:
- Turn off the phone and take the battery out. Put the phone in a bowl of rice after drying all the water you can off. Leave the phone off for a day or 2.
Note: If the phone is damaged, I.e. won't turn on, buckling somehow, etc. You may have to take it to the phone shop to see if they can do anything. There are waterproof cases to help avoid this. A plastic sand which bag makes a lovely waterproof case for cheap. As well, I have never heard of the recovery of a phone that has been underwater that long. Asking them what parts are damaged could be a great place to start, maybe you can replace them yourself.
Some sources say that rice does not work, but putting a rag over a vacuum cleaner and sibling the water out can help. Use rice as a extra precaution.
Never use hair dryers and never lie to the phone store about there being water in the phone. They can tell by indicators and the heat dan harm the phone.