Persons who wish to enter Germany, for example for the purpose of taking up employment, within the framework of family reunification, or for studies, are required, upon entry, to have ongoing private health insurance coverage comparable to the provisions of Book V of the German Social Code (SGB V), unless statutory health insurance coverage already exists. This health insurance coverage must include the benefits to which persons insured under the statutory health insurance scheme are entitled pursuant to Section 11 (1)–(3) SGB V.
The insurance contract must be of unlimited duration and must not contain any expiry or termination clauses related to a specific age, the cessation of an activity, a change in the purpose of stay, or the loss of a lawful residence status.

In the case of family reunification, proof may be provided by submitting a letter from the (private or statutory) health insurance provider stating that you will be unconditionally included in the family insurance upon entry into Germany.

If this is not possible, an incoming insurance policy may be submitted. In contrast to a regular travel health insurance policy, it must not contain any resolutory conditions in the event of a long-term stay. The incoming insurance must be valid for 90 days (3 months) from the day of entry into Germany.
(It must cover the entire Schengen area, provide coverage of up to EUR 30,000, and must not contain exclusions such as coronavirus infections, etc.)

In the case of employment, insurance coverage must be ensured from the start of the employment contract. Proof may, for example, be provided by a letter from the (statutory or private) health insurance provider stating that you will be unconditionally admitted to health insurance from the date of entry.

If, for plausible reasons, entry into Germany is to take place a few days before the start of employment (e.g. to arrange the relocation), an incoming insurance policy must also be taken out for the period until the start of the employment contract.

Please note that the validity of the visa can only begin on the date from which you provide proof that sufficient health insurance coverage exists in Germany.