River Thames: current river conditions

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 in your area.

Current river conditions: updated 19 September 2026

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.

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.

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.

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

When these yellow boards are displayed, the Environment Agency advises:

River flows are likely to strengthen, and strong stream boards could be displayed very soon and without further warning.