There is a small medical clinic in Jungut Batu with an attendant doctor. This is a perfectly good facility for treating minor ailments, but visitors with anything approaching a serious problem should get back to Bali as quickly as possible. Opening hours are erratic and unpredictable. Ask at your hotel.
Like all of Bali, Nusa Lembongan is officially a malaria-free zone. Dengue fever is a potential problem. Unlike in mainland Bali, there are no recent cases of rabies.
This is a safe island and reports of crime, major or minor, are rare. Most common is the theft of items left in unlocked rooms, so as you would anywhere in the world, just be sensible.
Drugs are not especially widespread here, but you may be offered marijuana or mushrooms, and more rarely, harder drugs. Be aware that the former is highly illegal in Indonesia and penalties are harsh. The Indonesian legal position on mushrooms is unclear and to be totally safe, visitors should steer clear.
The biggest dangers to visitors are related to the sea. Swimming is not be taken lightly in any waters around Bali, and Nusa Lembongan is no exception. Mushroom Bay and the area around the mangroves in the north are largely safe for swimming, but still take care. Swimming at Dream Beach and Sunset Beach in particular should be avoided by all but the very strongest of swimmers, and even then with great caution. Surfing at all four breaks is challenging for beginners.
talk
Balinese is the most common language of communication between local residents, with Bahasa Indonesia a distant second. The Balinese spoken here is a distinct dialect, and sharp-eared linguists would certainly notice this. English is widely understood and spoken, often with an Australian accent!
telephone
It is possible to make phone calls from Nusa Lembongan. Although a little pricey, public telephone offices wartels can be found at the Scoot boat office and at Bungalow No7.
International phone operators: 101.
International Direct Dialing prefix: 001, 007, or 008.
The area code for Nusa Lembongan is officially 0366, although 0361 is also widely used.
Landlines are not that common, and even many well-established businesses operate with mobile telephones only. All of the major Indonesian mobile networks have coverage of the island.
For directory inquiries, dial 108 from a landline or 0361-108 from a mobile phone.