The Longest Tunnels in the World: Road, Railway, Subsea and Canal

• 883entries listed
• 57.1 kmlongest bore
• 1802–2025openings span
• 3720.54 kmtotal length

The longest tunnels in the world, ranked by length

How this archive measures: lengths, bores, dates and ordering

Road tunnels: what counts and what does not

The catalogue holds 883 entries with a recorded length, each giving a name, a length in metres and, where documented, the year of opening. The median entry measures 2.23 km, so half the catalogue sits below that and half above, which is a better guide to the typical structure here than the headline figure.

The tail of the distribution is where most of the engineering interest sits, which is why nothing is trimmed from the bottom of the catalogue. The middle half of the catalogue runs from 1 km to 4.94 km, and that band is where most of the engineering in the catalogue actually sits.

The shortest recorded entry is 0.05 km against 57.1 km at the top, a spread of 1241.39x across the same catalogue. The three longest entries alone account for 161.4 km of the 3720.54 km in the catalogue, which is 4 per cent of the total from 3 of 883 rows.

The ordering gives longest tunnels in the world by length, which is the comparison most readers arrive wanting. Sorting on that one dimension is imperfect, since geology decides difficulty, but it is the measure published consistently enough to rank on. Railway tunnels run longer than road tunnels on the same crossing because of gradient limits.

Between the longest and the tenth-longest the drop is 28.86 km, which is the part of the catalogue that changes when a single scheme opens. Where one of these 883 lengths disagrees with an operator's own figure for the world, the catalogue keeps the published value and notes the difference instead of averaging the two.

Railway tunnels and the gradient problem

Roughly 217 of the dated entries opened in this century, which is a rough measure of how much of the network is recent. Lengths for the world are recorded in metres which is how the operators publish them and why the shortest entry here reads as 46 m and not a rounded figure.

A new scheme in the world would have to beat 57.1 km to change the head of this catalogue, and that is the figure worth rechecking when one opens. 173 of the 883 entries fall within a quarter of the median length, which is how tightly this particular list clusters around its typical structure.

The 883 rows for the world are ordered by length, not by date, so the 2025 opening sits well down the catalogue without being any less current. The longest entry is 1241.4 times the shortest and 25.6 times the median, which is the quickest measure of how uneven the catalogue is.

Treat the tables as the argument and the prose as the footnote: the numbers carry the case. Road entries cover bores open to general traffic, not service galleries. The shorter half of the catalogue totals 471.95 km against 3248.59 km for the longer half, from the same number of rows.

Subsea bores, rock cover and gradient

Eighth in the catalogue is Shenzhen at 35.66 km, which is where the catalogue stops being about record holders and starts being about ordinary infrastructure. By the twelfth entry, Rogfast at 26.66 km, the differences between neighbouring rows are small enough that the ordering is sensitive to how each was measured.

Road tunnels are measured portal to portal along the carriageway. Subsea bores run beneath a fjord or strait with rock cover, not water, above the lining. 87 of the dated entries opened from 2010 onwards, which shows how much of what is listed here is recent construction and not historic work.

Canal tunnels, the oldest class in the record

The dated entries fall across 117 different years, which is a rough measure of whether this was a sustained programme or a handful of separate schemes. The ten longest average 42.76 km against 3.77 km for everything below them, and that ratio is the clearest thing this catalogue says about the distribution.

216 of the 883 measured entries exceed five kilometres, and those are the ones that carry a full ventilation and escape regime. Laid end to end the entries in the catalogue would run 3720.54 km, which is a number with no engineering meaning but a useful sense of the scale of what is catalogued.

Railway entries are measured along the track centre line. Nothing in these tables is estimated: where a value could not be sourced it is left blank. 2 entries sit within ten per cent of the longest, so the head of this record is a close group, not one structure standing clear.

Subsea tunnels are pumped continuously, and their low point sits well below sea level. Canal tunnels are the smallest and oldest class in this record. Cut-and-cover is faster and cheaper where the depth allows it, and it is the reason some urban entries have no portal in the ordinary sense.

Canal entries are measured along the navigable channel. This page records the records catalogued for the world in a tunnel almanac maintained at this address since the late 1990s. After the 2000s the next busiest decade here is the 1990s with 76 openings, so the building effort came in more than one wave.

The rock a tunnel is driven through outlives the traffic forecast that justified it, which is one reason old bores are so often reused. An immersed tube is floated into place and sunk into a dredged trench, so its length is set on land before it goes in the water.

Anyone comparing these figures across borders should read the note column too, since national practice varies. The longest entry is Gotthard Base, at 57.1 km, opened in 2016. The longest stands 3.25 km clear of the next longest, which is the margin to watch when a new scheme is announced.

Second and third place go to Seikan at 53.85 km and Channel tunnel at 50.45 km. Further down the catalogue, Shanghai Airport Link is recorded at 40.19 km and Songshan Lake at 38.81 km. Box girders replaced trusses on medium spans because they are stiffer in torsion and cheaper to maintain.

Dated entries run from 1802 to 2025, and the busiest decade is the 2000s with 130 recorded openings. 223 entries fall below a kilometre, short enough that portals and approaches usually decided their cost more than the bore itself. Subsea tunnels are usually built with a low point well below sea level and pumped continuously.

441 entries sit above the median and 442 at or below it, so the catalogue is top-heavy and not clustered at one end. 82 entries reach ten kilometres and 21 reach twenty, a distribution that decides how much of this catalogue needs full mechanical ventilation. Older entries were compiled from printed sources and correspondence, not from online publication.

Dates for the world refer to opening to traffic, not breakthrough, so the 1802 entry was under construction for some years before that. Openings average one every 0.4 years across the dated entries here, though they arrive in clusters, not at that rate. The Faroese crossings connect islands that had no fixed link at all within living memory.

The dated entries carry 117 distinct opening years across 223 years, and the median opening year is 1997. The earliest dated entry is Marseille Canal, France, opened in 1840, and the most recent is Tianshan Shengli in 2025. Toll plazas sit outside portals rather than inside them, for ventilation reasons as much as for traffic ones.

Rack railways climb where adhesion alone cannot, and their tunnels are short, steep and unlike anything on a main line. The note column is often the most useful part of a row, recording tube counts, gradients, closures and reconstruction dates. Catenary needs headroom that a road tunnel does not, so an electrified bore is taller for the same traffic.

The 2000s account for 130 openings here and the 1990s for 76, so the building effort was not spread evenly across the period. Segmental linings arrive precast and are bolted up behind the machine, so the finished bore appears at the same rate the face advances. A tunnel is funded on a traffic forecast and judged on a construction cost, and the two are rarely revisited together. Seismic risk changes the lining rather than the alignment: a tunnel is among the safer places to be in an earthquake.