Te Ava Fuagea is the deepest (13 meters) of the three passes into the Funafuti lagoon; the others are only about eight meters deep. Large container ships can enter the lagoon and tie up to the main wharf.
Yachties beware: Funafuti is probably the most poorly beaconed port of entry in the Pacific. At last report all the navigation buoys had disappeared from Te Ava Fuagea, making it an eyeball entrance. Navigation within the lagoon is also dangerous as it's studded with unmarked shoals, so yachts should proceed carefully along the marked channel to the anchorage off the main wharf. From October to April, westerly winds can make this anchorage risky.
Immigration is in the Government Offices near the airport terminal. Funafuti is the only place where yachties can clear in and out of Tuvalu. If you get permission to also visit Nukufetau (the only other Tuvalu atoll with a navigable lagoon) or Nanumea (which also has an anchorage), you must still return to Funafuti to check out of the country.
You can buy diesel oil at the BP depot just north of the main wharf at prices 35 percent less than those charged at the Funafuti Fusi supermarket. Sammy's Service Station next to the Fusi and Mama's Petrol at the south end of the airstrip also sell gasoline and diesel.
To refill scuba tanks, try the workshop that supervises maintenance on Tuvalu's patrol boat at the main wharf. First, however, get authorization at their main office opposite the hotel. If that fails, the Conservation Area Office at Funafuti Town Hall can refill scuba tanks.