The law restricts the distribution of plastic straws, among other foodware accessories, including compostable plastic straws. Acceptable single-use straws (such as paper straws) can only be made available upon request.
Aviso Oficial
NUEVA LEY ENTRA EN VIGOR EL 1.º DE JULIO DE 2019 (PDF)
Placard for Retail Establishments ("Straws available upon request" - printable sign to post at your establishment)