GTA Vice City The Party Walkthrough

Complete The Party in GTA Vice City by collecting Tommy's suit, visiting Colonel Cortez's yacht and taking Mercedes to the Pole Position Club.

Mission walkthrough

Collect the right outfit

Start at Ken Rosenberg's office, then follow the clothing marker to Rafael's. Walk into the marked pickup to change into the suit. This is a required stop; going straight to the marina leaves the preparation unfinished.
Board the yacht

Drive to Ocean Bay Marina and approach the yacht's entrance on foot. Follow the marker into the party scene. The guests introduce several contacts who become important later, but you do not need to explore the whole deck or speak to everyone manually.
Give Mercedes a lift

After the scene, use a vehicle with space for Mercedes and wait until she gets in. Follow the new club marker and stop in the destination area. Avoid starting fights or attracting police while she is following you: this is a transport objective, with no reward for speed.
Continue Ken's mission chain

The delivery completes the job and pays $100. Return to Rosenberg for Back Alley Brawl. The suit and Tommy's normal street clothes become available as outfit pickups.

Before driving away from the marina, check that Mercedes is actually in the vehicle. Reaching the club alone does not complete her delivery.