The bus, carrying 24 passengers, was travelling to Barcelona city airport from the Costa Brava resort of Lloret de Mar.
It flipped onto its side by an industrial park just after 3am this morning.
A spokesman for a local emergency services coordination centre said: “Three are serious. There were Irish, British, German, Polish, Lithuanian and Belarusian nationals on the bus.”
Seven ambulances took the injured parties, including the driver, to the hospital.
While most casualties suffered only light injuries, three were seriously injured.
The nationalities of the seriously injured are unknown.
Heavy rain was initially blamed for the incident, leading the ring road to be closed for two hours.
- Irish dog walker stumbles upon dead dolphin washed up on Spain’s Costa del Sol - 18 Feb, 2019 @ 13:33
- BREAKING: British airline goes into administration with ALL flights to Europe cancelled, cites Brexit as major factor - 16 Feb, 2019 @ 20:10
- WATCH: New Marbella Arena to host string of ‘international artists’ and events this summer after signing deal with global events company - 15 Feb, 2019 @ 15:06
- ‘ABSOLUTE CHAOS’: Ryanair flight from Glasgow to Malaga diverted after violent ‘hen party brawl’ - 15 Feb, 2019 @ 13:37
- War to be waged against plastic in Gibraltar following deaths of ‘magnificent’ birds - 15 Feb, 2019 @ 11:18
- CASTING CALL: US Netflix series to film in Malaga and Marbella and needs extras THIS WEEKEND - 14 Feb, 2019 @ 14:38
- Neanderthal FOOTPRINT found in Gibraltar by crack team of British and Spanish scientists - 14 Feb, 2019 @ 14:08
- Elderly couple discover multiple sets of human remains in newly bought home on Spain’s Costa del Sol - 14 Feb, 2019 @ 13:27
- ANOTHER bank leaves Gibraltar ‘thanks to Brexit’ as opposition party calls on government to encourage big businesses to stay on the Rock - 13 Feb, 2019 @ 17:53
- British drug dealer cuffed ‘outside military establishment’ in Gibraltar carrying large amounts of cocaine - 13 Feb, 2019 @ 15:37