The objective of this study is to investigate the effectiveness of an innovative technique for strengthening masonry arches at their intrados, based on the use of carbon plates. Although FRP sheets or strips are successfully used as strengthening elements for this kind of application, they present several critical issues that can compromise these upgrading works, leading to the local collapse mechanism, which corresponds to the debonding of reinforcement from the masonry substrate. As an alternative to FRP sheets, the use of FRP plates presents instead several interesting aspects which make them very attractive for intrados strengthening. More precisely, FRP plates have an inherent bending and axial stiffness that may overcome problems concerning premature peeling. Fifteen prototypes of brickwork arches strengthened at their intrados with GFRP sheets or CFRP plates were tested under a monotonic vertical load applied at the keystone. The influence of the types of reinforcement (glass fibers and carbon plates), properties of the bonding system and masonry substrate and the presence of anchor spikes has been investigated.