This, says the regulator CNMC, was 1.4 million than at the same time last year.
Meanwhile, the number of DSL lines fell by 0.7 million in the 12 months to March 31.
CNMC notes that Movistar, Orange (including Jazztel) and Vodafone (including Ono) accounted for 81.5% of the fixed broadband lines.
Furthermore, the indirect access service NEBA (FFTH and copper) gained 13,530 lines in March, reaching a total of 979,307.
The number of local NEBA lines also increased to 1,784,362.