Traffic on the link over the Clyde between Inverclyde and West Dunbartonshire was halted for around ten minutes at 4.05pm today, the official Traffic Scotland information service said.
Environmental campaigners Greenpeace had said it was confident its ship would fit under the bridge without the need for a closure.
It said the Rainbow Warrior, with some 16 crew on board, was leaving the Clyde after dropping off four activists for the COP26 climate change conference.
The group also defended the time of the vessel’s departure, saying the river authorities had provided set times so a pilot could go aboard to accompany the ship.
Traffic Scotland tweeted: “Police Scotland will close the #A898 Erskine Bridge for a short period of time late this afternoon for public safety."
After the crossing re-opened, it tweeted: “Traffic heavy in the area.
“Westbound delays onto the #M8 10 mins.
“Eastbound delays on the #A82 heading into Glasgow.
The decision provoked a storm on social media, 24 hours after the bridge was closed for Rainbow Warrior’s arrival.
Darra Mc tweeted: “2 hrs yesterday for a journey that takes 20mins everyday. Diversions means more congestion and pollution. Great thinking.”
No place like home tweeted: “This is a disgrace. I don’t understand the rationale behind closing the bridge, took 1hr 45 minutes to get home yesterday and will no doubt be the same again.”
However, a Greenpeace spokesperson said: “We were 100 per cent confident on the way in that there were no issues.
"The captain had done all the calculations and measurements, and we knew we would be able to fit under the bridge with the water at certain levels.
"We empathise with the concerns, but it was not our decision to close the bridge.
"We spoke to the authorities who gave us set times to leave the dock with a pilot.”
The ship had berthed overnight at George V Dock, outside the COP26 river exclusion zone, just east of the Braehead shopping centre.
A Police Scotland spokesperson said: “The bridge is closing to ensure the safety of the public whilst the vessel makes its passage through the Clyde.”