Nusa Lembongan is one of the three islands belonging to the subdistrict of Klungkung and is about 12km away from Bali. The island is roughly 8 square kilometer in size, and you can hike it from one end to the other end in about 4 hours. Be prepared - there are some hills to climb and some interesting places are only reachable on foot, walking on dusty roads or small paths thru the wilderness.
Lembongan offers some nice sandy beaches made out of grounded corals and not as powdery as you might expect.
If you love swimming in the Ocean, be aware of some really strong currents, depending on the tides. Low tide means literally the water is gone and on high tide there can be really big waves.

So swimming is not for the faint of heart, and you should consult the tide schedule to be on the safe side. If you are a surfer, you will love the places here.
Lembongan is one of the places where you can find rare underwater creatures like the giant sunfish or Mola Mola, which is exactly the reason I went here. There are some really marvelous places nearby at Nusa Penida where you can encounter Manta rays, various sharks, turtles, hordes of coral fishes and corals in many different forms and colors.
If you like to relax, do spend some days here and you will not regret it. Life is simple, and food is inexpensive compared to European prices. A meal starts at 2 Euros. I can recommend the Warung (a familiy owned diner) where the locals like to go.

The speedboat to Lembongan at Sanur beach, prepare to get wet from knees down when boarding.

Getting to Nusa Lembongan from Bali is quite easy. Grab a cab from Denpasar airport and ask the driver to bring you to Sanur beach. Be careful, there are some taxi drivers at the airport who charge double the price. At Sanur, you can find several speedboat operators. I can recommend Rocky Fast Cruises, as they offer good services at reasonable prices - transfer shuttle to/from airport and hotel, with well maintained boats. They run four times a day. It is just a 30 minute trip to Jungut Batu.
The minibus transfer to your hotel or homestay in Lembongan will take only a couple of minutes as the island is not very big.

Homemade pimped vehicle to transport water and other goods - not for transporting tourists :)

Life in Lembongan compared to Bali is really relaxed. Scooters are the most popular mode of transportation on this island and nobody cares about driving rules or security. So be aware to be confronted with bikes and cars without headlights in the night, or scooters operated by kids as young as 6 years old, transporting friends or several family members. The source of major income is generated by tourism, followed by seaweed farming. The seaweed is cultivated near the shore, hand-picked, dried and sold to cosmetic companies. See more...

I have planned to go to Lembongan in September, as during this time, I would have a big chance to see some of the shy and imaginary sunfishes.
I booked a couple of dives at the Blue Corner Dive center and joined their day trips to places around Nusa Penida. I have seen a lot of different dive sites all over the world but I was impressed with the beautiful diving places here such as Mangrove Point, Crystal Bay or Toyapakeh. When diving here, you should bring at least a 5mm wetsuit as the water temperature can drop as low as 18 degrees Celsius. See more...

In case you like the simple life and do not have high demands for comfort, this island is a great place to relax. I loved the smell of the ocean and the warm breeze which gets refreshingly cooler at night time. During my stay, I was not bothered by any mosquitoes but the omnipresent cock crows can be annoying during twilight time. However I took that opportunity to enjoy the picture-postcard sunrises and sunsets.