Before moving to Spain from the UK you need to make sure that you apply for a European Health Insurance Card (EHIC, known in Spain as a Tarjeta Sanitaria Europea) which has now replaced the former E111 form and several other healthcare forms.
Application forms are available either at a UK Post Office or at the UK Department of Health website www.dh.gov.uk/en/index.htm. This is a very simple form to complete and once you have received your healthcare card it entitles the holder to healthcare at any hospital throughout Spain at a reduced cost or free of charge in some cases.
An EHIC will only cover you for emergency healthcare treatment in Spain. Remember though that this really is just for tourists, but will ensure that you do not end up having to pay for treatment during your first few weeks or months in Spain.
If you are planning to retire to Spain, if you are unemployed before you leave the UK, if you are a student, or if you are self-employed and planning to work in Spain, then you will be entitled to two years worth of full healthcare. See the Department for work and Pensions website, www.dwp.gov.uk for further details. Remember though that even with the forms you get from the DWP you will still need to become registered at the offices of the Spanish seguridad social. This process can take some time so make sure to get your EHIC card anyway.
Private health insurance is widely available in Spain, and in particular on the southern coast there are many schemes specifically aimed at British ex-pats.
The Spanish health-care system itself is actually very good. Most hospitals, especially on the southern coast, are modern, well equipped and the doctors and pediatricians are excellent. There are very few differences in policy between the British and Spanish health systems.
If you are planning to live in Spain then do remember that many medical staff do not speak English, even in resort areas. In some tourist towns a voluntary translation service is available for doctor's appointments but that will not be available at all times. It is a good idea to find out whether or not such a service exists in your local medical centre when you first arrive in Spain and if so at what times it operates. So at least try to pick up at least some basic Spanish before you arrive and have a look at the Chestertons affinity Language section for some helpful information.
Most ambulatorios or centros de salud (health centres) have a dentist who will provide free treatment to people registered with the social security system. You may also find dentists offering emergency treatment in Spanish hospitals. If you have any problems getting an appointment with the dentist at your local health centre then private dental treatment is widely available and prices are very low compared to private treatment in the UK. For private dental work expect to pay around 10 euros for a checkup and 40-50 euros for a white filling compared to around £200 per white filling in London, UK!
Many medicines that are prescription only in the UK are available over the counter in chemists in Spain, including Asthma inhalers and antibiotics. If you are registered for free healthcare under Spanish social security you can get medicines you need on prescription for a 60% discount, or for free if you are a pensioner otherwise, over the counter medicines and tablets can be very expensive.
Chemists or pharmacies are called farmacia in Spanish and they usually have a green or red cross outside. They're opening hours tend to be Monday to Saturday 9.30am to 1.30pm and 4.30pm to 8.00pm. The details of the nearest 24-hour pharmacy (farmacia de guardia) will be shown on any pharmacy door.