Most of the natural vegetation in the park is not tropical rainforest, which requires year-round rain, but rather coastal savannah, with deciduous trees that become bare in the dry season. The southern slopes receive more rainfall, and so have more tropical vegetation, while the coastal lowlands have extensive mangroves.
There are more than 200 species of plants growing in the park. Local fauna includes leaf monkeys and macaques (seen in the afternoon along the main road near Sumber Kelompok); rusa and barking deer; and some wild pigs, squirrels, buffalo, iguanas, pythons and green snakes. There were once tigers, but the last confirmed sighting was in 1937 – and that one was shot. The birdlife is prolific, with many of Bali's some 300 species found here, including the very rare Bali starling.
Just getting off the road a bit on one of the many trails transports you into the heart of nature.
By land, by boat or underwater, the park awaits exploration. You'll pay 250,000Rp to 350,000Rp to enter the park, depending on the day, plus another few thousand rupees for your activity within the park. You'll also need a guide and negotiating this fee can be confounding. Virtually all costs are variable. You can arrange things at the park offices in Cekik or Labuhan Lalang. Iwan Melali is a knowledgeable, English-speaking guide who excels at tracking down wildlife.
The best way to explore the mangroves of Teluk Gilimanuk (Gilimanuk Bay) or the west side of Prapat Agung is by chartering a boat. Let the fixed prices at nearby Banyuwedang be your guide to negotiating your price: a boat (for one to 10 people) is 600,000Rp and a mandatory guide (for the group, many do little actual 'guiding') 235,000Rp. Additionally, there is snorkel-set rental per person 40,000Rp; and park-entrance fees per person 250,000Rp to 350,000Rp, plus diving/snorkelling fees 25,000/15,000Rp.
All hikers must be accompanied by an authorised guide. It's best to arrive the day before you want to hike and make arrangements at the park offices.
The set rates for guides in the park depend on the size of the group and the length of the hike – about 350,000Rp per hour for two people for up to two hours is the starting price. Transport costs and the price is negotiable. Early morning, say 6am, is the best time to start – it's cooler and you're more likely to see some wildlife.
If, once you're out, you have a good rapport with your guide, you might consider getting creative. Although you can try to customise your hike, the guides prefer to set itineraries, including some of the following sites.
From Sumber Kelompok, hikes head up Gunung Kelatakan (Mt Kelatakan; 698m), then down to the main road near Kelatakan village (six to seven hours). You may be able to get permission from park headquarters to stay overnight in the forest – if you don't have a tent, your guide can make a shelter from branches and leaves, which will be an adventure in itself. Clear streams abound in the dense woods.
A three- to four-hour hike will allow you to explore the savannah area along the coast northwest of Teluk Terima. You have a chance of seeing monitor lizards, barking deer and leaf monkeys – you may even spot a Bali starling, part of a release project in the park. The trek includes a ride to and from the trailhead.
From a trail west of Labuhan Lalang, a three-hour hike exploring Teluk Terima (Terima Bay) can begin at the mangroves. You then partially follow Sungai Terima (Terima River) into the hills and walk back down to the road. If you're lucky, you might see grey macaques, deer and leaf monkeys.
The closest options are top end and although there is camping, you must pay the park fee each day plus another 10,000Rp for a campsite. However, there's a large variety of options in Pemuteran, which is 12km east, and one decent budget hotel about 500m from Cekik.
Bring a picnic for a day trip. For a meal, head to Gilimanuk or Pemuteran.