Cruise ships in the Tafea Province, currently are only stopping in Mystery Island in Aneityum. This has created a unique tourism industry specifically in this area. There are many tours available and day activities and services such as massage and souvenirs available for purchase.
Mystery Island offers many tours that can be purchased on the day of the Cruise ships arrival and you can even trade in Australian Dollars on Mystery Island.
The Aneityum Island Page has some more details on Mystery Island or check with the Vanutau Tourism site for extra information on cruise ship travel.