Long distance train travel is done with DSB, the Danish State Rail system. (http://www.dsb.dk) A number of long distance bus companies also operate. Each region in Denmark has its own local public transportation company. For public transportation trains, buses and ferries use the online travel planner Rejseplanen (http://www.rejseplanen.dk...)?. There are two ways to buy tickets. For local trips you can buy a ticket from the regional transportation company based on a zone system. This ticket is valid on all public transportation including DSB trains for one to two hours depending on the number of zones you travel. Most public transportation companies offer a number of passes which can save you a substantial amount on transportation. In the greater Copenhagen region, the zone system is complemented by a system of âklippekortâ, punch cards. These cards come in a variety of colors where the color signifies the total number of zones one can travel through for each punch. So a two zone card punched once allows one an hour of travel throughout two zones. A two zone card punched twice in the same machine is valid for travel in four zones or from the airport at Kastrup to the main train station in Copenhagen. DSB also uses a similar system of klippekort/punch cards for travel in the Oresund region.
To use a klippekort/punch card, you insert the card, face up, into the yellow machine on the train platform. You will hear a clunk as a punch discard is removed from card. Repeat to add zones. The machine will also have a zone map and a guide to explain how many punches it takes to travel from where you are to where you want to go. Most regions have their own klippekort but they do not work between regions. Some of the long distance bus companies offer klippekort that are valid for a specific route across regions but these are probably of little use for travelers as they have to be bought on cards of 10 punchestrips.
By ship
The only way get to most of the smaller islands, is by ferry. There are 55 domestic ferry routes in the country. The two most important ferry companies are Nordic Ferry (http://www.nordic-ferry.com/) and Mols Linien (http://www.mols-linien.dk...).
Ferries are the best way to get to Bornholm, a Danish island in the Baltic Sea, although it also can be reached by plane. Since the opening of the bridge to Sweden, the easiest route from Copenhagen to Bornholm is by train and then ferry from Ystad. Through tickets are available from Copenhagen and Ronne - booking is mandatory. There is also a bus that serves this route - Gråhund Bus 886 from Copenhagen to Ystad, where it links with the ferry to Bornholm
By bike
Biking in Denmark is, in general, safe and easy. Drivers are used to bikes everywhere, and all major cities have dedicated, curbed bike lanes along the main streets. Denmark is quite flat, but can be windy, cold or wet on a bike. Bikes are generally allowed on trains separate ticket sometimes needed.
Note that biking on the expressways Da: motorvej is prohibited, and that this also includes the Great Belt Bridge and the Ãresund Bridge. Trains can be used between Nyborg and Korsør and between Copenhagen and Malmö if you need to cross the bridges.
Official marked routes across the country can be found in the guides on this page: (http://www.trafikken.dk/w...)
By train
The primary Danish train company is Danish State Railways or DSB (http://www.dsb.dk). Many feeder lines for the principal train line in eastern Jutland are now operated by British company Arriva. Other small rail lines are operated by other companies. DSB also operates the S-Tog commuter rail system around the greater Copenhagen area. Eurail passes are valid on all DSB trains. Danish trains are very comfortable, very modern and very expensive. Tickets can be purchased in stations, from vending machines in the stations and via DSB's website. In addition to a ticket, some trains require a seat assignment. Most trains have 230V power outlets.
If you are not travelling on a rail pass, try asking for a Orange ticket, these are a limited number of heavily discounted tickets that are available on most departures. They are often sold out way in advance, but it never hurts to ask - and you do need to ask, in order to get the discount. Unfortunately due to worn out rails, the intercity trains are often late, though as many other railways suffer from similar issues, this is of course very relative, and both funding and a comprehensive 36 billion kroner plan to deal with the problem, has passed through parliament, although it will take many years to remedy years of neglect. All trips with trains and local buses can be scheduled electronically through Rejseplanen.dk (http://www.rejseplanen.dk...)?.
By road
It is quite easy to hitchhike in Denmark. People who pick up hitchhikers usually speak English. Destination boards are recommended. It is illegal to hitchhike on the highways, so it is better to use highway-entrances and gas stations. When crossing by ferry, try to get into a car that already paid for the ticket.
If you hitchhike from the southern part of Denmark direction from Hamburg or Kiel, Germany, and continue in direction to Copenhagen, make sure the driver doesn't stop in Kolding. If he does, ask him to stop at the last gas station before Kolding. On the Kolding highway crossing there is no place to hitchhike and it is one of the worst places in Europe for hitchhikers.
Check out the Tips for hitchhiking article here on wikitravel if you are new to hitchhiking.
By plane
Scandinavian Airlines (http://www.scandinavian.net/), Norwegian (http://www.norwegian.com) and Cimber Air (http://www.cimber.dk/) all operate domestic routes, all of them either from or to Copenhagen Airport, there is no domestic routes between regional airports. Since most of the country's airports were build as military airfields during the second world war, they are often inconveniently located far from town centres, which as a general rule make train travel nearly as fast from town centre to town centre for destinations less than 3 hours by train from Copenhagen. For destinations further afield trains will often get you where you want to go a lot cheaper, albeit competition is heavy, and it is indeed sometimes possible to find plane tickets cheaper than the train, if you book well ahead of your planned departure - this is especially true for the Copenhagen - Aalborg route, where both traffic and competition is heaviest.
Airports with domestic traffic are: Copenhagen, Billund, Aarhus, Aalborg, Karup, Sønderborg and Bornholm.
Some of the more remote islands, if there is any such thing in a country as small as Denmark, also sees regular taxi flights from Roskilde airport to their small airfields, on-board small propeller aircraft. The most traficed route are between Roskilde and the islands of Læsø and Anholt, where there are daily flights bookable on-line or by phone. These flights tend to be fairly expensive though, with the price hovering around 1000 DKK for a one way ticket.
By bus
Long distance bus-service between Jutland and Copenhagen is possible with the company Abildskou line 888 (http://www.abildskou.dk/), and while cheaper than the train, the difference is less pronounced than in many other countries, A ticket between the countries two largest cities; Aarhus-Copenhagen for instance, is DKK 270 One way for adults with Abildskou versus DKK 350 with the train. If you are flexible there is considerable discounts available in certain departures, where tickets can get as low as DKK 180, if you buy your tickets in advance.
See also the overview at: Fjernbusser.dk.