Battle of San Juan ( 1625 ) The Battle of San Juan was fought on 29 September 1625 , and was an engagement of the Eighty Years ' War . A Dutch expedition under the command of Boudewijn Hendricksz attacked the island of Puerto Rico , but despite besieging San Juan for several months , was unable to capture it from Spain . Battle . On 24 September 1625 , 17 Dutch ships arrive at San Juan de Puerto Rico , whose Spanish governor — naval and military veteran Juan de Haro y Sanvitores - had been in office less than a month . Nevertheless , he prepared to receive the enemy as best he could , sending his predecessor , Juan de Vargas , to nearby Boquerón with militia to hinder any landings in Escambrón Inlet . Hendricksz implemented a bold plan . At 1 : 00 P . M . the next day the entire Dutch fleet sailed directly into San Juan ’ s harbor : < br > " Roode Leeuw , Witte Leeuw , Leyden , Blauwe Leeuw , Goude Valck , Utrecht , Nieuw Nederlandt , Hoop van Dordrecht , Kleyne Tijger , Hoorn , Medemblik , Gouden Molen , Vlissingen , West Kappel , Goude Sonne , Koningin Hester " , and " Jonas " . They exchanged shots with the harbor castle , inflicting superficial damage and killing four Spaniards , before gaining a safe anchorage within the roadstead off Puntilla Point , beyond range of de Haro ’ s artillery . However , shoals prevented an immediate disembarkation of troops . The delay allowed Spanish civilians to flee inland , while the governor marshaled his slender strength within San Felipe del Morro citadel . He installed six additional bronze 12 - pounders in its embrasures and mustered 330 men , of which 220 were effective . He also had abundant supplies ) . < br > On 26 September , Hendricksz led 700 – 800 men ashore and occupied the empty city . Two days later the Dutch also occupied the small , wooden El Cañuelo fort , which stood on a rock islet in the harbour . The main citadel proved impossible to storm , so the Dutch began digging saplines and installing a six - gun battery atop Calvario Heights by 29 September . At 9 : 00 A . M . the next day Hendricksz called upon de Haro to surrender . de Haro rejected the offer so action resumed . Capt . Jan Jasperz de Laet of " West Kappel " exited the harbour on 1 October to chase away a Spanish ship arriving with supplies . On the night of Friday , 3 – 4 October , the Spaniards sallied out of their citadel in two companies of 40 men apiece under Capts . Sebastián de Avila and Andrés Botello , but accomplished little . They enjoyed better fortune at noon on 5 October , when 50 men under Capt . Juan de Amézquita y Quixano destroyed the advance Dutch works , killing a captain , a sergeant , and eight sappers . Guerrillas from the interior under Capt . Andrés Vázquez Botello de Carrera also began plaguing the besiegers . On the night of 5 October they killed Nieuw Nederlandt ’ s captain and a 20 - man boat party in the harbor . Ten days later they destroyed a similar force up Bayamón River . By October 16 the guerrillas had grown so bold as to recapture El Cañuelo . A force of 30 men in two launches arrived and killed two of its Dutch occupiers , capturing another 14 . < br > Faced with this increased pressure , Hendricksz found himself trapped inside the harbor . He again called upon de Haro to capitulate on 21 October , threatening to burn the city , but was again rebuffed . Hendricksz then put San Juan to the torch , and the Dutch reembarked at 10 : 00 A . M . the next day , hotly pursued by Puerto Rican units . The invaders now had to run the gauntlet of Spanish artillery in order to escape , which led them to hesitate for a full fortnight before they finally fled on 2 November . Aftermath . The 30 - gun , 450 - ton " Medemblik " ran aground and was left behind for the exultant Spanish . Juan de Amézquita boarded her and extinguished the slow fuse that was burning toward her magazine . Sadly , De Haro was unable to savor the victory because a cannon had exploded near him during these final exchanges , spraying him with two dozen fragments that eventually killed him . Hendricksz , meanwhile , retired to San Francisco Bay for a month to recover from the setback . In addition to the loss of " Medemblik " , numerous other Dutch vessels had sustained damage , and 200 men have perished ( as opposed to 17 Spanish fatalities during the siege ) . Hendricksz nonetheless detached his five best vessels on a privateering cruise toward Santo Domingo before attempting to lead his entire fleet west again in late November . Driven back by storms , he cruised south toward Isla Margarita ( Venezuela ) , despite advance warnings having preceded him .