Shore Diving

The majority of diving on Timor Leste's north coast is easily accessible from the shore with the closest site just 5 minutes drive from the dive centre. The shore dive sites consist of sloping reefs and walls with the tops of the reefs starting from just 2-3 metres and descending down to depths of 30-40 meters with some shear walls even dropping 60+ metres allowing everything from snorkeling, recreational diving and even technical diving directly from the shore.

Blue trim nudibranch,Credit

The local dive sites around the Dili area range from Tasi Tolu area to Christo Rei beaches and offer some excellent diving from beautiful corals and reef fish to excellent macro dive sites with all the interesting critters. Being so close into Dili makes it easy to head out for a dive any time at these sites as well as offering some top night dives.
The coastal dive sites are approximately an hour drive either to the east or west of Dili and offer many more dive options including some of the deeper walls. These are normally dived as day trips from Dili doing 2-3 dives and bringing lunch to enjoy under the shade of a tree on the beach between dives. The drives also follow some exceptionally beautiful coastline as well local villages and some old colonial relics.

Longnose hawkfish,Credit

Boat Diving

Atauro is the primary destination for boat diving in Timor Leste and the 25 kilometre boat ride to the island usually reveals dolphins, pilot whales as well as larger whales especially in season from November to February. Boat dive day trips to the island leave from Dili harbour and include 2-3 dives and lunch before returning.
On the east side of the island the dive site Outer Reef is a sloping reef that offers for a great drift dive and is usually the place that when lucky, divers spot hammerhead sharks especially early in the morning. Manta Cove is a sheltered dive site with shear wall dropping down to around 80 metres. Along the western coast of the island dive sites Frank's Crack and Table Top are known for deep walls covered in hard and soft corals and plenty of life. On the southwest corner Big Fish dive site is only for experienced divers due too very strong currents but can get huge schools of pelagics.

Blue Starfish,Credit

The Pinnacle is an excellent boat dive site that is just a few minutes out of the Dili harbour and excellent site for pelagics, reef sharks and turtles. This pinnacle rises from about 40-50 metres to the top of 12-14 metres and can have strong currents at times.

Reference
http://www.divereport.com/locations/south-east-asia/timor/timor-leste/#diving