| Conflict: | Action of 30 September 1639 |
| Partof: | Dutch-Portuguese War |
| Date: | 30 September 1639 |
| Place: | Near Mormugão, south of Goa, India |
| Result: | Dutch victory |
| Combatant2: |  Portuguese Empire |
| Strength1: | 9 ships |
| Strength2: | 3 galleons 10 or 12 unarmed "frigates" |
| Casualties1: | Unknown |
| Casualties2: | 3 galleons captured and destroyed |
The action of 30 September 1639 was a naval battle near Mormugão, just south of Goa, India, when a squadron of 9 Dutch ships captured and destroyed 3 Portuguese galleons.
The Portuguese galleons Bom Jesus 74 and São Sebastião 50 were being careened and had their guns removed and were captured without fighting. Bom Jesus was set alight and allowed to drift toward the new galleon São Boaventura, which was refusing to surrender, causing São Boaventura to catch fire and blow up. Some of the unarmed "frigates" approached toward the end but were frightened off by the Dutch boats. The Dutch had a total of 261 guns, 810 sailors, and 170 soldiers on their ships.