The State Pension (Contributory) is paid to people from the age of 66 who have enough Irish social insurance contributions. It is not means-tested. You can have other income and still get a State Pension (Contributory). This pension is taxable but you are unlikely to pay tax if it is your only income.
As the social insurance conditions are very complex you should apply for a State Pension (Contributory) if you have ever worked and have any contributions (stamps) paid at any time. There are a number of pro-rata pensions available to people who paid different types of social insurance contributions or who did not pay contributions because of various reasons (see below).
If you retire early, you should ensure that you continue to pay PRSI contributions or get credited contributions (if eligible) to maintain your entitlement to a pension. If you are getting Jobseeker's Benefit (JB) and are aged between 65 and 66 when your JB would normally end, you may continue to receive it until the age of 66, provided you meet the PRSI requirements.
The Department of Employment Affairs and Social Protection (DEASP) has published FAQs on Qualifying for the State Pension (Contributory) which can help you to work out whether you qualify for a State Pension (Contributory).
The means-tested State Pension (Non-Contributory) is a payment for people aged over 66 who do not qualify for a State Pension (Contributory) or who only qualify for a reduced contributory pension based on their insurance record.
This pension is taxable but you are unlikely to pay tax if it is your only income