the northern coast
Madang is good for scuba diving of all levels,and the coral reefs are home to a variety of rare species of colorful fish. There are also underwater wrecks of Japanese fighter planes, with weapons and cargo intact. There are still-active volcanoes for trekkers to hike up not far from Madang.
Further west you come to Wewak. It is the gateway to the Sepik River region with a fascinating culture distinct from that of the Highlands. Take long canoe rides up the river and it's tributaries to visit the impressive Haus Tambaran's (http://en.wikipedia.org/w...).
the islands
New Britain. This island offers excellent swimming and snorkeling. Trails in the area are perfect for day hikes and treks through the rainforest. There are also hot thermal springs and bubbling mud holes in this region of the island. The Baining people who inhabit the northeastern area of New Britain are famous for creating ephemeral art-forms, perhaps no better demonstrated than by their firedance. A dramatic and beautifully made mask is constructed from bark for this ceremony and thrown away as worthless immediately afterwards.
Bougainville. Well off-the-beaten-path in the far east of the country, with great untapped tourism potential. World-class diving, dramatic treks and World War II Japanese relics are the key attractions.
Trobriand Islands. The so called Islands of Love are well known for their unique culture.
south new guinea
The Kokoda Trail is a 60-mile trail, beginning in the Port Moresby area and leading up into the Owen Stanley Range. This trail was first used by gold miners in the 1890s and is most known as a historical World War II site as the Japanese tried to reach Port Moresby along it. It takes about five days to hike this track, which includes plenty of ups and downs between mountain ridges and streams.
the highlands
The Highland region is made of long string of fertile valleys, each separated by mountains, that mean the Highlands are composed of many distinct tribal regions.
In the Eastern Highlands is Mount Wilhelm, Papua New Guinea's highest mountain 14,880 feet. Climbing Wilhelm is relatively easy; but three or four days are recommended to allow for sightseeing. There are views of both the north and south coasts of New Guinea from the peak. The Wahgi River in this area is considered one of the best whitewater rafting destinations in the world.