List of longest tunnels
This list of longest tunnels ranks tunnels that are at least long. Only continuous tunnels are included. Pipelines, even those that are buried, are excluded. The longest tunnels have been constructed for water distribution, followed by tunnels for railways.
World's longest tunnels (in use)
World's longest tunnels (under construction)
World's longest tunnels (advanced planning stage)
| Type | Name | Location | Length | Year | Comment |
| Road & Rail | Taiwan Strait Tunnel | / Taiwan Strait | 150,000 m | ??? | Plans to link Taiwan and Mainland China as part of the G3 Beijing–Taipei Expressway. Approved since 2013 on Chinese side |
| Railway | Bohai Strait tunnel |  Bohai Strait, China | ??? | Tunnel between Dalian on the Liaodong Peninsula and Yantai on the Shandong Peninsula. | |
| Railway | Talsinki |   Helsinki, Finland – Tallinn, Estonia | after 2030 | Awaiting financing | |
| Water supply | Qinling Tunnel, Han River Diversion to Wei River | Shaanxi, China | ??? | ||
| Railway | Mont d'Ambin Base Tunnel |   Cottian Alps, France – Italy | 2029 | Part of the Lyon-Turin high-speed railway. Reconnaissance tunnels under construction; start of construction planned for 2019 | |
| Metro | Athens Metro Line 4 |  Athens, Greece | 2028 | Start of construction planned for 2019 | |
| Metro | Mass Rapid Transit : Cross Island Line |  Singapore, Singapore | 2029 2030/2031 | Start of Phase 1 construction planned for 2020 Phase 2 route not announced | |
| Railway | Barrandov Tunnel |  Prague – Beroun | ??? | Project is on hold | |
| Road and railway | Fehmarn Belt Fixed Link |   Germany–Denmark | 2028 | Start of construction planned for 2020 | |
| Road twin tube | Kresna Gorge Tunnel |  Kresna, Bulgaria | cancelled | Part of Struma motorway, connecting Sofia and Athens. | |
| Road twin tube | Agua Negra Tunnel |   Chile–Argentina | ??? | Awaiting ratification by Chile | |
| Ship Tunnel | Stad Ship Tunnel |  Selje, Norway | 2023 | Canal tunnel. Possible construction start in 2021 |