Tides and currents: A beginner’s guide

If you are new to boating and keen to explore the UK’s waterways, you must know about tides. While many canals and rivers aren’t significantly affected by tides, some are. Waterways nearer to the coast or in estuaries, like the Thames, can be noticeably affected by tidal changes. It is vital to understand tides and currents before you take to the water to avoid getting stuck on a sandbank or, worse, causing an accident or having to be rescued. To get maximum benefits from your boating experience, brush up on your knowledge of tides and currents.

Here, you’ll find everything you need to know to keep you out of tidal trouble.

All about tides

We all know that tides happen. But what drives them?

There are two high and two low tides each day around Britain. These tides are driven by the gravitational pull of the moon and the sun on the rotating planet Earth. This natural phenomenon generates tidal force, which causes very long-period waves to move through the ocean (where tides originate) and progress towards shorelines.

Read more about the science behind tides here.

The timing of high and low tides changes daily because of the changing positions of the moon and sun relative to Earth.

If you are boating, you must have a tide timetable. Many apps, such as TidePoint, Tide Times UK, or Tides Near Me, provide this information.

Alternatively, search for UK tide times here.

You will encounter a term called ‘tidal range.’ This is the difference in height between high tide and low tide.

Tide timetables forecast the times of high and low tides at a particular location along with the height of the tide (usually in metres), so they are only predictions. Wind direction, atmospheric pressure, and heavy or prolonged rain can raise the tide level, so these factors must also be considered.

What are Spring and Neap tides?

In addition to everyday tides, twice monthly, when the sun, moon and Earth line up, the gravitational pull increases, causing exceptionally high and super low tides called spring tides. The highest spring tides of the year are called king tides.

Spring tides occur during a new or full moon. ‘Spring’, in this context, has nothing to do with the season; it’s a historical term derived from the concept of the tide ‘springing forth’.

Neap tides happen seven days after a spring tide when the sun is at a right angle to the moon. With neap tides, high tides are a little lower, and low tides are a little higher than average, meaning the difference between high and low tides is minimal. These tides occur when the moon appears half-full.

Check out the spring and neap times for Europe in 2025 here.

What you need to know about currents

When boating on the tidal Thames or any waters, boaters need to be aware of strong currents. These can vary considerably depending on weather conditions and tides. They can also be particularly strong in the lower reaches of the river. Strong flows occur at low and high tides.

Boaters should also be aware that bridges, piers, slipways, and other structures in the water can create swirls and eddies – these are pockets of water created when the current pinches off from the main flow. Eddies can cause boaters to get stuck in a circular current, making it difficult to manoeuvre. Skilled boaters use eddies to their advantage, but this is not recommended for beginners.

The Environment Agency issues’ strong stream’ warnings when currents are too strong for safe navigation, so checking this before boating is essential.

See the River Thames’s current conditions here.

How do tides and currents affect boating navigation?

Tidal forces can change the direction and speed of your boat, and strong tidal currents can even take your boat way off course.

Experience is required to navigate strong currents, which involves changing speed and adjusting direction. Safe water navigation can become a problem when currents are particularly strong, especially for smaller boats and beginners.

Tides also change the water’s depth, making it troublesome for boats when the water becomes too shallow. It’s critical to know how the tides affect water depth and where this occurs to prevent your boat from running aground. This can also happen without you realising if you are anchored.

Careful planning is essential. Boaters should consider the tide’s height and the current’s direction and strength to determine the best route and time to make their journey. Accurate data is essential, so always gather information from a trusted source.

View tide tables for 706 UK locations here.

Download tide times and port information for the River Thames here.

Tides and currents must be respected, but with careful planning, they can be used to your advantage. As a beginner, however, it is always best to err on the side of caution when taking to the water. If the river is high, weather conditions aren’t great, and red boards are  displayed, you should not consider taking your boat out.

Tides and currents: Interpreting weather forecasts

It’s always good practice to check the weather the night before when considering a boating trip. Don’t forget that recent rain may mean the river is running faster than usual and there can be a lag between rainfall and increasing currents. Boating in Autumn, Winter, and early Spring, when there is more rainfall, causes additional challenges for boaters. You may encounter reduced bridge height, and mooring can be tricky if the tops of mooring locations are obscured by water. There can be the added risk of hidden underwater debris dislodged by faster river flow.

Always check for flood alerts and weather warnings.

To interpret weather forecasts for boating, pay attention to wind speeds and direction, visibility, precipitation, and cloud cover, and be aware of specific warnings about conditions.

Understanding tides on the River Thames

The tidal Thames is a unique estuary stretching approximately 95 miles from Southend to Teddington. Because it is connected to the North Sea, it is affected by two low tides and two high tides each day. A safe boating trip requires knowledge of the tidal stream and its effects.

Key terms regarding the Thames tides you need to know are flood tide, ebb tide and slack water.

• A flood tide refers to the rising tide where water flows upstream.
• An ebb tide is the opposite of a flood tide. It occurs when water flows downstream or seaward.
• Slack water is the brief period between the flood and ebb tides when there is little movement, and the water is relatively still with minimal current.

Beginner boating tips: Practical tips for safe boating

Always plan your journey. The Port of London Authority website has tide tables, live tide times for the tidal Thames, and a handy tide prediction tool. There’s also lots of information about ship movements and navigational safety.

Tide times, current information and weather forecasts should always be something you check before planning your trip out on the water and not something you do on route as an afterthought.

The Canal and River Trust offers several downloadable waterway guides that contain boating maps, navigation notes, and information on locks and bridges, services and facilities, and visitor moorings.

Regular maintenance checks on your boat and equipment are also essential. In the Autumn and Winter, you should pay extra attention to lifejackets, ropes, fenders, batteries, drain holes, fuel levels and the bilge pump(s).

The main basic rules while you are on the water include:

• Keeping to the right and passing port side to port side
• Keeping a safe distance from the bank
• Keeping a good lookout (in front and behind you)
• Always allowing plenty of manoeuvring room
• If you are faced with the situation of approaching another vessel head-on, sound one short blast and keep to the right
• At bridges, use the most starboard arch available to you (providing it is safe to do so)

Learn more about the key rules for motor boating on the tidal Thames here.

How to plan your tidal journey

With knowledge and respect for tides and currents and an understanding of how the weather can affect them, there is no reason why you can’t have a safe and brilliant experience in tidal waters.

When planning your boating journey, always follow these four steps:

1. Check tide tables.
2. Understand how wind and weather interact with tides.
3. Use navigation tools and apps.
4. Research the locks that you will be passing through (if applicable) e.g. St Katharine’s Dock

As a beginner, it’s a good idea to practice boating on more minor routes before venturing further afield.

Common boating mistakes on tidal waters

• Not accounting for a tide change when anchoring
• Navigating too close to shallow waters during low tide
• Underestimating the speed of a current
• Ignoring weather forecasts
• Overloading the boat
• Failing to check tide times before setting out

Conclusion

Understanding tide and currents and how they affect you on the water is essential for a safe and enjoyable boating experience. This will require a bit of studying, choosing appropriate navigation tools, and practising your boating skills in the safest waters first.

If you need advice on boating safely, check out our numerous boating guides or contact our experienced team. One of our boating experts is always on hand and happy to help.