Here is some information about How to Register with the Centro de Saude / Health Centre.

Firstly the Cartão de Utente used to be a blue plastic card, this is no longer issued as the Cartão Cidadão (Citizens card) is replacing all personal plastic cards, and so you will be issued with a printed A4 document which shows your Numero de Utente (Health Service User Number). This should be produced whenever Health care is needed, either at the health centre, pharmacy or hospital. 

It is important that people who are living in Portugal know what they are entitled to and how to register and use the systems here. There is much discussion and speculation about this subject. There are also some Health Centres (Centro de Saude) who do not seem to know how their own system works, so here is the current information whatever your Retired or Working status is here. The following guidance is for all residents in Portugal. The British Consulate have been very helpful in assisting with the information in the article, and it is correct as of January 2017.

Similarly to the UK, the Portuguese Health System is residency based. In short, this means that anyone who is legally resident in Portugal is entitled to state healthcare. However, the way the system is accessed may be different depending on individual circumstances.

A British person who:

1. a) moves to Portugal on early retirement, would register as a resident with their Town Hall first and then, armed with their Certificado de Registo and British passport, register for health care and apply for a Numero de Utente at their nearest health centre or social security in some towns.(However, please note that when "early retirees" reach pensionable age and begin receiving a UK state pension, they should ask the DWP (International Pension Centre,Tyneview Park, Newcastle-upon-Tyne NE98 1BA) to send them a Form S1 (formerly E121) so that they can register this with their nearest Social Security office. This will enable the Portuguese authorities to receive payment for the healthcare they provide to pensioners from the DWP);
2. b) moves to Portugal on retirement and is in receipt of a UK state pension, long term incapacity benefit or bereavement benefit, would apply for a Form S1 from the DWP International Pension Centrein the UK, register this form at their nearest Social Security Office and then register at their local health centre.Though pensioners do not need to show evidence of residence for the purpose of registering for health care, they should still register as residents with their Town Hall and obtain a Certificado de Registo;
   DWP Phone Number (0044) (0)191 218 7777
3. c) moves to Portugal and takes up employment or is self-employed, would register as a resident, obtain a social security number through his/her employer or by registering with the Social Security authorities in order to make contributions as a self-employed person, and then register for health care and obtain an Numero de Utente from his/her local health centre;
4. d) is posted to Portugal by his UK employerto work for a period of up to 3 years and continues to pay social security contributions in the UK, would obtain a Form S1 from HM Revenue and Customs, CAR - Residency, Room BP1301, Benton Park View, Newcastle-upon-Tyne NE98 1ZZ before leaving the UK, register as a resident with their local Town Hall on arrival in Portugal, then take the Form S1 and Certificado de Registo to their local Social Security office for registration.The Social Security authority will keep one copy of the S1 and return the other copy, stamped and signed, to the new resident. This copy can now be used to access healthcare.

With the exception of category b) above, people who do not register as residents will be considered to be visitors to Portugal and will only be entitled to emergency medical treatment. For this purpose, they will be asked to show a valid EHIC. Note that under Portuguese law when you have been in the country for 3 months you should register as a resident at any Town Hall.

Check out these other articles;

Fees for the Health Service (coming soon)

How to Book an Appointment online. (coming soon)

European Health Insurance Cards

Healthcare in Portugal