How Deep Are Canals in the UK?

There is no singular figure for how deep canals are in the UK, but most cruising canals are around 1-1.2 metres deep in the main channel. However, some locks have deep vertical drops of up to 6 metres.  

Discover the deepest known parts of Britain’s canal network, what affects canal depth, and why depth is important to know about. 

How deep are British canals? 

The average depth of canals in Britain varies due to the landscape they pass through and the way each waterway was built. Canals aren’t static structures, despite being man-made to transport freight vessels during the Industrial Revolution. As the water is constantly moving, boat traffic and the weather shift mud and debris around. This is also known as silt, which settles at the base of the canal and creates irregular depths across the waterways.  

There are over 2,000 miles of canals and rivers throughout England and Wales and over 140 miles in Scotland’s network, so there are hundreds, if not thousands, of different measurements at different points in the water.   

The deepest vertical part of the UK’s canals is 6 metres (19.7ft) at Tuel Lane Lock. 

But there are over 2,100 miles of varying waterways, so no one part of the canal will measure the same depth as another!  

Where is the deepest canal lock in the UK? 

The deepest known measurement of a canal lock in the UK is six metres (6m) at Tuel Lane Lock near Halifax, on the Rochdale Canal. This measurement is the vertical drop of the lock and not the depth of the cruising water your boat is on.  

Tuel Lane Lock was constructed in 1996 as part of the Rochdale Canal's restoration and designed to replace two less efficient locks from the canal's original structure. Its design is a testament to its efficiency, replacing two old locks with a single deeper one.  

As the drop is so deep, boaters are not permitted to operate the lock mechanism themselves. Instead, the lock keeper of the Canal & River Trust will guide you through the gates. 

Looking for a canal route to take you there? The South Pennine Ring from Anderton Marina guides you through Tuel Lane Lock, five canals and three of the Seven Wonders of the Waterway, across 21 nights with 6.5 hours of cruising per day.  

EXPERIENCE THE UK'S DEEPEST LOCK

The second deepest canal lock in the UK, Bath Deep Lock, is only slightly shallower than Tuel Lane Lock, coming in at 5.92 metres. It follows a similar story, as this lock was also constructed to replace two locks which were working ineffectively. On the Bath and Return route from Hilperton Marina, you can experience operating a lock in deeper waters, as this one is manually operated.  

The deepest draughts of popular UK canals 

The draught of a canal refers to the maximum usable depth in the main navigation channel under normal conditions. Most UK canals are only about 1.0-1.2m deep in the middle, which is perfect for narrowboats like ours at ABC Boat Hire.  

Using data from the Canal & River Trust, these are 15 of the deepest draught sections of UK waterways: 

How deep was the Llangollen Canal breach in 2025? 

The Llangollen Canal breach was reported to have created a hole around four metres (4m) deep. The ‘embankment failure’ incident happened on 22 December 2025 near Bridge 31A by Whitchurch, Shropshire, and left two boats stranded at the bottom of the canal and another peering over the trench's edge. Gallons of water flooded local fields, with the recovery operation set to extend into much of 2026.  

A spokesperson for the Canal & River Trust emphasised their robust inspection scheme, and there were no causes for any intervention or undue concern at the time. 

ABC Boat Hire’s routes to Llangollen from Whitchurch or Blackwater Meadow are not affected. If you require any assistance or have any questions about the incident, please contact our team.   

Why is canal depth important? 

It’s crucial to be aware of canal depth when boating, as not every inch across the water will be the same depth as advertised, and if not steered properly, you could bump your boat.  

Canals are usually deepest in the middle, which is where boats travel, but the bed slopes up towards both banks. If you steer too close to the side, your boat may touch the bottom of the bed even though the official depth seems fine. This also depends on your boat’s draught, which is how deep the narrowboat sits in the water.  

Knowing about canal depth is also important for: 

1. Navigation and safety  

Maintaining adequate canal depths is crucial for safe navigation. Shallow canals can lead to the grounding of boats, while deeper canals ensure smooth passage and reduce the risk of accidents. Proper depth management is essential for the safe and efficient operation of canal traffic.  

2. Environmental considerations  

The environmental aspects of maintaining canal depths include the impact on canal wildlife, water management, and local infrastructure. Well-managed canals support diverse aquatic life, and it’s a part of the Canal and River Trust’s mission to keep this green corridor and its habitats thriving. Any sudden changes in depth and drainage can harm this. 

Want to travel to the depths of the UK canal network? 

Explore our most popular canal boat holiday routes and short breaks to find your perfect staycation today.  

If you’re researching canals and narrowboats, you may also want to read:

• Can you go fishing on canals? 

• How were canals built? 

• How far can canal boats travel? 

• How do locks work? 

• What’s the difference between an aqueduct and a viaduct?