As a door that connected Bali to Lombok, padang Bai has a harbor for some of ship to carry a people to moving trans island to Lombok island. Its quite cheap to go to lombok by fery, and only take about 20 minutes. even you can take your car also. Better than by plane that will cost you about 3 until 5 times much expensive cost.
In padang Bai you also can see a white sand shore, and lot of traditional fishing ship that still oftenly used by the traditional fisherman aroud the Village.
If you have plan to swim, Padang Bai is a good place to go.
North of the Bay, you can visit the Silayukti Temple. The temple consist of four major Temple and some of small temple around it. People in Bali believe Silayukti is one of the Oldest Temple in Bali.Legend say that Silayukti Temple was built by Empu Kuturan, a sacred priest from Java, that introduce the caste system to Bali in 11'th centuries. Every six balinese month, or excactly 210 days, there is a celebration in the temple. Most of Balinese people come to Silayukti Temple to pray, the celebration usually held in three days.If you have plan to stay for a vew days, there is some Hotel near the temple that you can visit.Maybe the Silayukti Temple is not famous as the Besakih Temple, but if you have time better you visit this place if you have plan to visit it as one of the east of Bali tourism area.