Phuket
If you're staying for longer than just the wedding, Phuket's got lots to see and do. There are also plenty of smaller nearby islands to explore, such as Ko Yao Yai.
For getting around, we highly recommend Grab (Thailand's version of Uber). It's trustworthy and affordable. Please note that if you order Grab from the airport, their pickup area isn't with the taxis, but outside gate 4 of the arrivals hall. Bolt also operates on the island.
You can also get food, drinks, and other stuff dropped off to you via Grab. Please don't drink the tap water, but it's fine for brushing your teeth.
Thai SIM cards are available on arrival at Phuket airport. These are safe and sold at official prices.
One more very important note: Grab drivers, as well as some hotel staff, might not speak English well or at all. Be patient and polite if you're having communication barriers. Google Translate will be more useful than saying the same thing in a louder voice.
And now, some more specific tips!
Phuket City
Phuket, จ.ภูเก็ต 83000, Thailand Phuket City, also called Phuket Town, is the island's capital. The resort has daily shuttles to and from Limelight Avenue, a mall in the city. They have a big and well-known night market (the Phuket Indy Night Market), and the Old Town is charming with lots of shopping opportunities.
Last time we were there, we went to a restaurant called Day & Night of Phuket and had an incredible lunch.
Patong
Pa Tong, จ.ภูเก็ต, Thailand Patong Beach and the surrounding town is Phuket's biggest party area. You'll find lots of bars, restaurants, and shopping in the area.
We stayed at the Kalima Resort near Patong, and also visited Thavorn Beach Village Resort. Both lovely spots.
The Big Buddha, Phuket
Karon, จ.ภูเก็ต 83100, Thailand Do you like gigantic Buddha statues? If so, you're in luck, cause Phuket has the world's 19th largest!
Kevin's never been here, but Antony has. He says it's neat if you're into big Buddhas.