Can I use an E101?
International Social Security
If you work in another EEA country for an EEA employer you are usually insured under the social security laws of the country you work in.
However, within the EEA it is possible, in some cases, to get an exemption from local social security via an E101 form if you are being seconded by an overseas (EEA) employer. This enables you to continue payments to the social security in the country of your employer rather than paying locally.
An E101 is valid for one year and in some countries can be extended annually (with the permission of the working country) for up to 5 years.
Paying social security is a legal obligation in your country of work and the E101 provides this legal coverage. It is also the case in most EEA countries that you will also be required to hold a valid EHIC card.