A white cross divides the flag into four quarters of blue (upper) and red (lower). In the canton, a start of white.
It is worth noting that for once, the Coat of Arms is inspired by the flag. At the end of May/beginning of June, 1868, in a meeting of the Junta Centro Bravo, don Manuel Rojas presented the design of a flag, imagined by Dr. Ramón [Ramo'n] Emeterio Betances, to be used as a symbol of the Grito de Lares and flag of Puerto Rico when the nation's independence would be gained. [FOTW]