This is the age when it’s all about hanging out with their friends and checking the guys/girls out. As much as parents may want to deny it, the cool factor is very important, particularly at a party... and adults aren’t welcome! The easiest way to go is to throw a pool party with a barbecue or finger food, and lots of it.
The great thing about teens is that you can pretty much leave them to it and they will entertain themselves, and they don’t expect party favours. That’s not to say you don’t cast the occasional cautionary look in their direction! A beach party theme always goes down well and it’s easy to get them to wear Hawaiian shirts and grass skirts. Rent or buy giant pool floats, get water guns and balloons, balls (rugby, volleyball, football) to throw, and be prepared for noise and action (find a good range of pool toys at Float Flow Online; floatflowonline. wix.com/floatflow). Always keep a cool box filled with ice and lots of drinks.