There’s a common misconception: if you work in Switzerland after having paid into the pension scheme in Spain, you’ll receive a pension from both countries, which is almost like earning double. The reality is rather more sobering, and understanding this in good time changes what you need to plan for.
The bilateral social security agreement between Switzerland and Spain, supplemented by the European coordination agreements applied in Switzerland, stipulates the following: each country pays its share, and only its share. If you contributed for 8 years in Spain and 22 in Switzerland, Spain calculates a pension as if you had contributed for 30 years, but only pays you 8/30 of that amount. Switzerland does the same with your 22 years. It is not double: it is proportional, and the total may be less than what you would receive if all your years were in a single system.
Where the agreement does help is with eligibility. If, in Spain, you need 15 years of contributions to be entitled to a contributory pension and you only have 5, Spain can count your Swiss contribution years towards meeting that minimum threshold. Once eligibility is confirmed, the calculation is based solely on the actual years of contributions in Spain.
Here’s the practical implication: if you’re thinking of returning to Spain as you approach retirement, the contributions you make in Spain during your final working years will count towards your Spanish pension base, which could significantly boost your Spanish pension. Working in Switzerland right up until the day before you retire isn’t always the most cost-effective strategy if you plan to live in Spain afterwards. It’s worth doing the maths beforehand, not when there’s no longer any scope to change anything.