You can visit Sefa-utaki located in the south of the main island of Okinawa and Kudaka Island using bus and ferry from Naha City.
Sefa-utaki and Azama Port Ferry Terminal where the ferries for Kudaka Island depart are located nearby, and you can get to them using the same bus (38 Shikiya Line) from Naha City.
Normally you can take the bus from Naha Bus Terminal near Asahibashi Station of Yui Rail (Okinawa Urban Monorail), but currently Naha Bus Terminal is under renewal construction (expected until March 31, 2018), so you need to go to temporary bus stops set up around the terminal.
38 Shikiya Line (志喜屋線) bus departs from Kamiizumi (上泉) bus stop (C). Walk to the south of Naha Bus Terminal following the signs for several minutes, then you will find Kamiizumi bus stop (C) in front of “oHacorte Bakery.”
The number of 38 Shikiya Line buses is around 1 to 2 in an hour. Refer to this page for the bus timetable (in Japanese). If you want to go to Kudaka Island, get off the bus at “Azama Sunsun Beach Iriguchi (安座真サンサンビーチ入口),” and “Sefa-utaki Iriguchi (斎場御嶽入口)” (beyond Azama Sunsun Beach Iriguchi) if you want to go to Sefa-utaki. The bus fare is 780 yen for “Azama Sunsun Beach Iriguchi,” and 830 yen for “Sefa-utaki Iriguchi.” You need to take a numbered ticket issued from the machine located next to the driver’s seat when you ride on the bus.
They don’t accept the notes except 1,000 yen, so you need to prepare money beforehand. It will take around 1 hour to both destinations.
The bus will be changed at a bus company’s office along the way. You don’t need to take a numbered ticket again on the new bus, and the bus fare should be paid together at the end of journey.
It takes around 10 minutes on foot to Sefa-utaki from “Sefa-utaki Iriguchi” bus stop. The distance from Sefa-utaki to Azama Port Ferry Terminal where the ferries for Kudaka Island depart is around 1 km, so if you have enough time, I recommend you go to Sefa-utaki first, enjoy the view of Kudaka Island in the distance from Sefa-utaki, and then walk to Azama Port Ferry Terminal to take the ferry for Kudaka Island.
If you want to directly go to Kudaka Island without visiting Sefa-utaki, get off the bus at “Azama Sunsun Beach Iriguchi” and walk in the direction of the sea, then you will reach Azama Port Ferry Terminal.
Azama Sunsun Beach is located next to the ferry terminal, so it would be nice to spend a relaxing time on the beach while waiting for a ferry. You can also find some cats around the ferry terminal.
The number of ferries to Kudaka Island is low, so it would be better to take a ferry departs in the morning if you visit the island on a day trip. Refer to this page for the ferry timetable (in Japanese). It takes only around 15 to 25 minutes on the ferry to Kudaka Island. There are two types of ferry (Ferry Kudaka and the high-speed ferry New Kudaka III), but it is decided depending on the departure time, so there is no room for choice if your departure time has already been decided. The ferry (Ferry Kudaka) fare is 670 yen for one way and 1,280 yen for round trip. The fare for the high-speed ferry (New Kudaka III) is 760 yen for one way and 1,460 yen for round trip.
Extra ferries may be operated on the days a lot of people visiting Kudaka Island such as the former New Year.