As long as you keep the amount under 10.000 euros or equivalent in different currency, you do not have to declare cash or cheques when passing border control.
Read for further info the website from Spain´s Treasury, in English.
http://www.tesoro.es/en/prevencion-del-blanqueo-y-movimiento-de-efectivo/movimientos-de-efectivo/preguntas-frecuentes
Please note: The information provided is based upon our understanding of current legislation. It is not legal advice but is provided freely to enable you to be properly informed. We recommend that if you are considering taking action, you should seek professional advice.
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