Handstruck markings began to be introduced early in the 19th century (1819 at San Juan de Puerto Rico) and by 1850 there were nine offices open. British PA was established on the island as early as 1844 at San Juan and this used a crowned circle handstamp until 1865. At that time British adhesives were introduced (oblit. C61), but were withdrawn the following year.

Further offices were opened in 1872 and stamps were re-introduced from 1873-7. Additional obliterations were issued as follows: Aguadilla (F83), Arroyo (F84), Mayaguez (F85) and Ponce (F88). A further office was opened in 1875 at Naguabo (582). There was a French PA at San Juan from 1865 and Mayaguez from 1876. Both offices used French stamps and were closed in 1877 when Spain joined the UPU.

First stamps issued were joint issues with Cuba which appeared in 1855 but were not generally used in Puerto Rico until 25 July 1856. First stamps with the name of the island appeared in 1873.

Spanish surrendered to American forces on 17 October 1898 and Puerto Rico was ceded to US on 10 December. Became a US Territory on 2 March 1917 and gained US Commonwealth status on 25 July 1952. American stamps overprinted PORTO RICO were used until April 1900 but unoverprinted American stamps have been used since 12 April 1900; US domestic postal rates apply.