The Bornholm Tunnel (Danish: Bornholmtunnelen) is a proposed railway tunnel which would be built between the island of Bornholm, belonging to Denmark, and Scania in Sweden. The tunnel would provide a fixed link to the island, both using direct trains running from Copenhagen and with a motorail service to transport automobiles. The tunnel would be 40 kilometers (25 mi) long and provide a one-hour transit time for cars, including loading and unloading, and a two-hour service by rail to Copenhagen via the Ystad Line and the Oresund Line. The latter could be further reduced with construction of high-speed rail in southern Scania.
Today the island is served by ferries operated by BornholmerFærgen from Rønne, the main town on the island, to Ystad in Sweden, Køge in Denmark and Sassnitz in Germany. Travel time from Ystad to Rønne is two and a half hours with conventional ferries and one and a quarter hours with fast ferries, with three to seven daily sailings combined. From Rønne to Køge takes five and a half hours and has a single daily sailing, while from Rønne to Sassnitz is seasonal and offered three to eight times per week and takes three and a half hours. DSB operates three daily train services branded as Intercity Bornholm from Copenhagen Central Station to Ystad Station, where passengers transfer to the ferries. Cimber Sterling operates flights from Bornholm Airport to Copenhagen Airport.
Costs for running the ferry service are DKK 400 million per year, of which DKK 150 million are subsidies. If the same user payment and subsidies was used to finance the tunnel, with a running time of 30 years, it would allow investments for DKK 10 billion. Estimates for the cost of the tunnel vary from DKK 5 to 50 billion.
The Danish organization Foreningen Bornholmtunnel and the Swedish organization Föreningen Stöd Bornholmstunneln collaborate to raise awareness about the importance of a tunnel between Bornholm and Scania.  The Bornholm province decided in April 2013 not to pay for a detailed investigation
- "København på under 2 timer" (in Danish). Bornholmtunnelen. Retrieved 19 November 2010.
- "Sejlplan 2011" (PDF) (in Danish). BornholmerFærgen. Retrieved 19 November 2010.
- "InterCity Bornholm" (PDF) (in Danish). DSB. Retrieved 19 November 2010.
- "København" (in Danish). Bornholm Airport. Retrieved 19 November 2010.
- "Minister kalder tunnel spændende" (in Danish). Bornholmtunnelen. Retrieved 29 April 2013.
- "Svensk opbakning til tunnel" (in Danish). TV 2/Bornholm. Retrieved 30 April 2011.
- Politisk nej til tunnel-undersøgelse