British Nationals do not require a visa for Bosnia and Herzegovina for a period of up to 90 days within a period of 6 months. If you wish to stay for longer than 90 days, you must apply to the Border Police for a Residency Permit. You will be required to show evidence that you have no criminal record in the UK. You will have to obtain this before you travel.
Ensure that your passport is stamped when you enter the country, as the Border Police may fine you when you leave if you do not have one. Your passport must be valid for a minimum of 90 days from the date of your departure.
All foreign nationals must register with the police within 72 hours of arrival. Usually, hotels and registered hostels will arrange this for their guests.
Children under the age of 18 years old travelling unaccompanied or accompanies by an adult other than their parents must carry a notarised letter from their parents giving permission for the child to travel. If the child is travelling with one parents, the accompanying parent should carry a notarised letter from the other parent giving permission to travel.