From the Carnival FAQ page. Carnival could update this information without notice.

Port of Tampa
The Seaport Street Terminal
651 Channelside Drive
Terminal #2
Tampa, Florida 33602

The Seaport Street Terminal is located in an area referred to as the Garrison Seaport Center and is adjacent to the Florida Aquarium.

Travel Time: 15 miles from the Tampa International Airport; travel time is approximately 20 minutes.

DIRECTIONS TO THE PORT:

Traveling from the North

I-75 South to I-4 West -OR- I-275 South to I-4 East.
Take Exit 1 - sign will read: Port of Tampa/Ybor City.
Take 21st Street south.
Turn right on East Adamo Drive/Highway 60.
East Adamo Drive/Highway 60 will turn into Channelside Drive/13th Street.
Bear to the left and follow signs for the Florida Aquarium/Seaport Terminal.
After dropping off your luggage at the terminal, the entrance to the parking garage will be on your left.

Traveling from the South

I-75 North
Take Crosstown Expressway west (toward Tampa).
Take 22nd Street north exit - sign will read: Port of Tampa/Ybor City.
Take 22nd Street north.
Turn left on East Adamo Drive/Highway 60.
East Adamo Drive/Highway 60 will turn into Channelside Drive/13th Street.
Bear to the left and follow signs for the Florida Aquarium/Seaport Terminal.
After dropping off your luggage at the terminal, the entrance to the parking garage will be on your left.

Traveling from the East

I-4 west.
Take Exit 1 - sign will read: Port of Tampa/Ybor City.
Take 21st Street south.
Turn right on East Adamo Drive/Highway 60.
East Adamo Drive/Highway 60 will turn into Channelside Drive/13th Street.
Bear to the left and follow signs for the Florida Aquarium/Seaport Terminal.
After dropping off your luggage at the terminal, the entrance to the parking garage will be on your left.

Traveling from the West - Tampa International Airport

I-275 North (stay in right lane).
Take I-4 East.
Take Exit 1 - sign will read: Port of Tampa/Ybor City.
Take 21st Street south.
Turn right on East Adamo Drive/Highway 60.
East Adamo Drive/Highway 60 will turn into Channelside Drive/13th Street.
Bear to the left and follow signs for the Florida Aquarium/Seaport Terminal.
After dropping off your luggage at the terminal, the entrance to the parking garage will be on your left.

PARKING:

$14 per day (Rates subject to change by the Port Authority)
Covered parking garage.
Full payment due upon entering the garage.
Accepted forms of payment: U.S. dollars, Visa, Mastercard, American Express, Discover Network®.
No advance reservations required.
Oversized vehicles will be charged per space, per day. For more parking information, contact: 813-905-5072