Before dealing with social-security contributions and tax.

Your own employment records / employment contract and actual working arrangement.

Employment contract, home address, work calendar and information about home office or work in several countries.

The employer's registered office or daily cross-border commuting alone is not enough to determine all social-security and tax rules.

Before starting or when changing the cross-border working arrangement.

The competent social-security institution; if Slovakia is competent, the Social Insurance Agency (Sociálna poisťovňa).

Details of employers, workplaces, share of work and residence.

For work in two or more countries, the employer’s seat is not the only factor; the state of residence and substantial part of activity also matter. From 1 Jul 2026 Slovak employers file applicable-legislation applications electronically.

After social-security responsibility is determined or when the work arrangement changes.

The competent health insurer/institution under the determined legislation.

PD A1 or another decision on the applicable legislation, if issued.

Do not create parallel public health insurance in two countries merely because a person lives in one and works in another.

Before annual tax settlement/return and when the working arrangement changes.

Slovak Financial Administration and the relevant double-tax treaty.

Days of residence and work, country of tax residence, income certificates and proof of tax paid.

There is no universal rule that tax is always paid only where the employer is based or only where you live; residence, place of work, type of income and the specific treaty matter.

Continuously during cross-border work.

Your own records.

A1, payslips, annual statements, employment contracts and insurance records.

These documents may later be important for tax, unemployment and pension claims.