San Martin completed her studies in Costume Design in 2001 (Inacap, Santiago de Chile), and went on to study Engraving and Printing Techniques at the Escola d’Arts i Oficis at La Llotja in Barcelona (2003-2004). In 2006, she enrolled at the IDEP school in Barcelona to study Pattern Cutting for the Performing Arts and Millinery with Nina Pawlowsky (2006–2007), at the Escola Massana.

For 25 years she has specialised in styling and costume design for theatre, working at the Teatre Liceu in Barcelona, at the Teatre Nacional de Catalunya, and with the Auditori de Catalunya.

San Martin has also designed costumes for various theatre, circus and dance productions, as well as for TV and film series.