Natural Resources Wales (NRW) has issued the reminder ahead of the school summer holidays, asking people to protect the environment, respect others and enjoy the outdoors safely.
With three heatwaves already recorded and more sunny weather expected, nature reserves, forests and national parks across Wales are expected to attract high numbers of visitors.
NRW said it has seen increased littering, fires, fly-camping, and mountain and water safety incidents in recent years.
Joseph Conran, lead specialist advisor for outdoor access and recreation at NRW, said: “Wales offers such an amazing backdrop for your adventures, and we love to give a ‘croeso cynnes’ (warm welcome) to responsible visitors.
“For many, the summer months are a time for relaxing and having fun.
“However, it’s also the busiest time of year in the outdoors, and can unfortunately lead to increased incidents of injury, damage to our environment or antisocial behaviour.
“The Countryside Code has been with us for 75 years as a gentle reminder of how we can respect the places we visit.
“By following its simple messages, you can feel confident that you are doing the right thing for yourselves, other people and the environment.”
A key concern this summer is wildfire risk, following the exceptionally warm, dry spring and early summer.
Visitors are asked not to light campfires, discard cigarettes or leave litter behind, particularly glass bottles.
Barbecues should be avoided during dry weather, and only used in designated areas where permitted.
Fly-camping, or camping without the landowner’s consent, is also discouraged due to its associated environmental risks.
Water safety remains a priority, especially as temperatures rise and more people are tempted to swim in open water.
NRW advises people to check for hazards, avoid swimming alone and choose lifeguarded beaches where possible.
The organisation monitors 114 designated bathing waters across Wales throughout the summer for pollution.
It recommends avoiding swallowing water and washing afterwards to reduce the risk of illness.
The Countryside Code includes key messages such as taking litter home, staying on marked paths, keeping dogs under control and planning your route in advance.
Visitors are also reminded not to block driveways or gateways and to treat locals and fellow visitors with respect.
The full Countryside Code is available on the NRW website.
