Short answer
Art. 71.1 of Ley 14/2013 requires a highly qualified employment or professional relationship. The Blue Card (art. 71.2.a) is tied to employment, so the ground in art. 93.1.b).1º LIRPF fits: a move made because of the start of an employment relationship with an employer in Spain (also on an ordered displacement with a carta de desplazamiento, or as teletrabajo).
The national modality (art. 71.2.b) covers employment or professional activity. If the relationship is employment, the same ground 1º applies. If it is professional rather than employment, ground 1º does not cover it directly; ground 4º remains, but only if its own conditions are met.
Art. 93 LIRPF conditions that apply to every ground
You must not have been a Spanish resident in the five tax years before the move. The regime applies in the tax year of the change of residence and the five following years, so up to six years. Main income is taxed on a scale of 24 % up to 600,000 € a year and 47 % above, with no deductions or offsetting, and savings income follows a separate scale. The procedure for exercising the option is set by the Ministry of Finance in a separate act: check it, and its deadline, before you file. The general analysis of the regime is in the article on digital nomad taxes.
What to pay attention to
- Employment or professional relationshipThe ground depends on it. An employment contract fits ground 1º; a professional relationship needs a separate check.
- A permanent establishment does not block the regimeFor the entrepreneurial and highly qualified professional grounds, the general bar on income earned through a permanent establishment does not apply (art. 93.1.c).
- Documents on the employer and the contractThe contract and proof of the start of the relationship are used to support the chosen ground.