With Ruling No. 20 of 2026, the Italian Revenue Agency clarified how the 183 working days must be calculated in order to exclude, pursuant to Article 51 of the Italian Income Tax Code (TUIR), the income earned by Italian seafarers working on foreign-flagged vessels from Italian taxation.

Such income is not subject to taxation in Italy if the activity is carried out abroad for more than 183 days within a 12-month period, regardless of the place where the work is actually performed. For Italian nationals, tax residence is also irrelevant, as already confirmed by Ruling No. 112/2023.

The 12-month period does not have to be continuous, as it does not coincide with the calendar year and may therefore span two different calendar years.

The calculation of the 183 days also includes holidays, public holidays, weekly rest days and other non-working days, provided that such days are provided for under the employment contract.