River Thames: current river conditions
Source: gov.uk (2025-12-11)

The current conditions affecting boaters on the River Thames and what the warnings mean.

Before you take your boat out on the River Thames, you should find out the current river conditions and make sure you understand what they mean. You should also check if there are any closures or restrictions (https://www.gov.uk/guidance/river-thames-restrictions-and-closures) in your area.

Current river conditions: updated 11 December 2025

We update our information about the river conditions and strong stream warnings once a day by 11am. You should also check the warning boards displayed at lock sites or talk to lock staff if you are using your boat on the river.

Lechlade to Oxford

Oxford to Henley

Henley to Teddington

What the warnings mean

Any river activity poses a greater risk when there are strong currents, high river levels or cold weather conditions. River flows can increase even during the summer months. Never assume that sunny weather means the conditions are not hazardous.

The Environment Agency may display warning boards at locks to inform river users of the conditions. Read the explanations of what these mean for you. Do not take risks and never underestimate the power of the river.

Strong stream warning

A red sign with white text reading 'Caution: Strong stream'.

When a strong stream warning has been issued, and red boards are displayed at our lock sites and on GOV.UK, the Environment Agency advises users of all boats not to navigate. The strong flows make it difficult and dangerous to navigate.

The flow of water close to weirs and sluices is particularly hazardous and a risk to life.

People in hire boats arriving at a lock where these boards are displayed should stop immediately. Contact your hire boat operator to ask for instructions.

Stream increasing warning

A yellow sign with black text reading 'Caution: Stream increasing'.

When these yellow boards are displayed, the Environment Agency advises:
- users of all unpowered boats not to navigate
- users of powered boats to find a safe mooring
River flows are likely to strengthen, and strong stream boards could be displayed very soon and without further warning.

The flow of water close to weirs and sluices is particularly hazardous and a risk to life.

Stream decreasing warning

A yellow sign with black text reading 'Caution: Stream decreasing'.

When these yellow boards are displayed, the Environment Agency advises:
- users of all unpowered boats not to navigate
- users of powered boats to navigate with caution
A stream decreasing warning board will be issued once a strong stream warning board is no longer required. The flow of water close to weirs and sluices, however, remains extremely hazardous and a risk to life.

Weirs and sluices

Keep well away from weirs and sluices at all times, but especially when any stream warnings are active.

Flow conditions may change unexpectedly and without warning when our weir assets are being operated, making these areas extremely hazardous and a risk to life.

Using navigation marks

When travelling upstream, keep red navigation buoys to your left and green navigation buoys to your right.

When travelling downstream, keep red buoys to your right and green buoys to your left.

You may pass single yellow marker buoys on either side.

In all cases, keep well clear of navigation buoys. Be aware of possible shoals on the inside of river bends.

Dealing with changing river conditions

If you find yourself in conditions where the Environment Agency advises you to stop navigating, please take the advice and stop. Even the most experienced boater can be caught out, so think about those who could be put in danger if they have to help you.

You may find the following measures helpful. Not all conditions will be serious enough to need all the suggested measures.

Moor your boat in a safe place, preferably in a marina or at a recognised mooring. Limited space may be available at some locks. Moor against high banks if you can.

Ensure your mooring lines are fastened to secure fixings such as bollards, rings or even trees. Put out extra lines for more security and allow enough slack for a further rise in river levels. Do not rely on your own mooring pins or stakes, as they might not hold.

If possible, put extra fendering (such as scaffold poles or strong timber posts) between your boat and the bank side. This may prevent your boat drifting onto the river bank and becoming caught up when levels drop.

Make sure you have a safe exit ashore from your boat. If not, consider returning home or finding alternative accommodation until conditions improve.

If you are not able to vacate your boat safely and are running low on essential supplies or have other safety concerns, treat this as an emergency. Dial 999 to ask for evacuation.

Those in hire boats should stop immediately if you are advised to stop navigating. Contact your hire boat operator and follow their instructions.

Please remember your life is more important than your boat.

The Environment Agency does not provide emergency services. We are not able to carry out search and rescue, or provide supplies to stranded boats.

Contact the Environment Agency

General enquiries

National Customer Contact Centre PO Box 544RotherhamS60 1BY

Email xxx@xxx.xx (mailto:xxx@xxx.xx)

Telephone 03708 506 506

Telephone from outside the UK (Monday to Friday, 8am to 6pm GMT) xx-xxxx-xxxx

Monday to Friday, 8am to 6pm.

Environment incident hotline

Contact form https://www.gov.uk/rep... (https://www.gov.uk/report-environmental-problem)

Telephone (24 hour service) xx-xxxx-xxxx

Floodline

Telephone (24 hour service) xx-xxxx-xxxx

Type talk (for the hard of hearing) xx-xxxx-xxxx