• Surf from Bali, Flores, Java, Lombok, Sumatra, Sumba and Sumbawa. Some well-known surfing beaches, such as Ulu Watu on Bali, tend to get overcrowded, but organised trips to isolated areas are widely available.

• Dive off the coastline, reputed to contain 15% of the world's coral reefs (website: www.underwaterindonesia.com).

• Probe caves on Java, including Luweng Jaran, stretching over 20km (125 miles) beneath the Gunung Seuw mountain range; Gua Barat, which has the longest underground river system in the southern hemisphere; and Gombong, whose stone towers rise spectacularly to some 40m (132ft) above sea level.

• Take a tour up the great Mahakam River in Kalimantan, Borneo, which is dissected by a network of rivers running from the mountainous interior to the coasts. Starting from the port city Samarinda, such tours continue deep into the upper jungle reaches, where tribal communities have largely preserved their traditions (website: www.visitborneo.com).

• Trek up an active volcano: on Java island, hike Krakatoa, Mount Bromo (the most visited of Indonesia's volcanoes) and Kawah Ijen (website: www.central-java-tourism.com). Those preferring dormant volcanoes may head to Gunung Agung in Bali, Gunung Rinjani on Lombok island (website: www.lomboksumbawa.com), and Keli Mutu on Nusa Tenggara Barat (website: www.ntb.go.id).

• Jungle trek through the Indonesian rainforest; Irian Jaya, Kalimantan and Sumatra offer the most remote and untouched terrain. The best trails include trips to Bukit Barisan National Park, a remote and beautiful peninsula in Sumatra and the Muller Mountain in Kalimantan.

• Take an eco-tour (website: www.indecon.or.id). Help preserve the coral reef in the Tukangbeshi archipelago near Sulawesi, by helping to collect scientific data.

• Cure any ills at the Holy Springs of Tampaksiring on Bali (website: www.balitourismauthority.net).

See Contact Addresses for further tourist information.