Sumatra, Java, Bali, Nusa Tenggara and Sulawesi are all connected by regular car ferries, and you can use them to island-hop all the way from Sumatra to West Timor. Local ferries run several times a week or daily (or even hourly on the busy Java–Bali–Lombok–Sumbawa routes). Check with shipping companies, the harbour office, travel agents or hotels for current schedules and fares.
Going to and between Kalimantan, Maluku and Papua, the main connections are provided by Pelni, the government-run passenger line.
Pelni (www.pelni.co.id) has a fleet of large vessels linking all of Indonesia’s major ports and the majority of the archipelago’s outlying areas. Pelni’s website is a good resource, showing arrivals and departures about a month in advance.
Its ships operate set routes around the islands, either on a fortnightly or monthly schedule. The ships usually stop for a few hours in each port, so there's time for a quick look around. Note that sailing times can be in flux until the last moment.
Economy fares can be quite cheap, but at higher levels of shipboard accommodation budget airlines are competitive if not cheaper.
Pelni ships range from modern, clean and well run to less modern, chaotic and dirty. Consider the following.
Booking Towns served by Pelni usually have a ticket office or agent. Book your ticket a few days in advance.
Classes Pelni ships have two to six classes. Economy class, which is the modern version of deck class, is a bare-bones experience. As you move up the price ladder, you exchange a seat on the deck for small accommodations until you reach a level that may give you your own private cabin with two beds (this is some variation of 1st class). These are functional at best and far from lavish.
Security There are no lockers, so you have to keep an eye on your gear if you are in any kind of group class. Beware of pickpockets when embarking and disembarking.
Crowding At busy times such as Idul Fitri, boats seem to have passengers crammed into every available space, including decks, passages and stairwells. Conditions can get grim.
Food Bring your own food and drink. Boats offer basic meals, or have shops offering instant noodles and snacks.
Boarding Getting aboard a Pelni ship can leave you bruised as it is truly every man, woman and child for him or herself as people try to get to scarce space first.
There's a whole range of boats you can use to hop between islands, down rivers and across lakes. Just about any sort of vessel can be rented in Indonesia.
Fast Ferries When available, these are a great alternative to the slow car ferries that link many islands.
Fishing boats Small boats can be chartered to take you to small offshore islands.
Longbot The longbot is a long, narrow boat powered by a couple of outboard motors, with bench seats on either side of the hull for passengers to sit on. They are mainly used in Kalimantan where they are also called klotok.
Outrigger boats Used for some short interisland hops, such as the trip from Manado in North Sulawesi to the coral reefs surrounding nearby Pulau Bunaken. On Lombok they serve the Gilis while Komodo National Park is served from Labuan Bajo. On Bali they are called jukung.
River ferries Commonly found on Kalimantan, where the rivers are the roads. They're large, bulky vessels that carry passengers and cargo up and down the water network.
Tourist boats Often very fast speedboats outfitted to carry 40 or more passengers, most commonly used for quick trips between Bali, Nusa Lembongan, Lombok and the Gilis.
Boat safety is an important consideration across Indonesia, where boats that barely seem seaworthy may be your only option to travel between islands. In many cases these services are accidents waiting to happen, as safety regulation is lax at best.
This is especially true on the busy routes linking Bali, Nusa Lembongan, Lombok and the Gilis, where both the fast tourist boats and the public car ferries have had accidents. Given Indonesia's poor record, it is essential that you take responsibility for your own safety, as no one else will.
Consider the following points for any boat travel in Indonesia.
Bigger is better It may take you 30 minutes or more longer, but a larger boat will simply deal with the open ocean better than the over-powered small speedboats.
Check for safety equipment Make certain your boat has life jackets and that you know how to locate and use them. In an emergency, don’t expect a panicked crew to hand them out. Also, check for life rafts.
Avoid overcrowding Travellers report boats leaving with more people than seats and with aisles jammed with stacked luggage.
Look for exits Cabins may only have one narrow entrance making them death traps in an accident.
Avoid fly-by-nighters Taking a fishing boat and jamming too many engines on the rear in order to cash in on booming tourism is a recipe for disaster.