Sea foam, ocean foam, beach foam, or spume is a type of foam created by the agitation of seawater, particularly when it contains higher concentrations of dissolved organic matter (including proteins, lignins, and lipids) derived from sources such as the offshore breakdown of algal blooms. These compounds can act as surfactants or foaming agents. As the seawater is churned by breaking waves in the surf zone adjacent to the shore, the presence of these surfactants under these turbulent conditions traps air, forming persistent bubbles that stick to each other through surface tension. Due to its low density and persistence, foam can be blown by strong on-shore winds from the beachface inland.
Where polluted stormwater from rivers or drains discharges to the coast, sea foam formed on adjacent beaches can be polluted with viruses and other contaminants, and may have an unpleasant odour.
If crude oil discharged from tankers at sea, or motor oil, sewage and detergents from polluted stormwater are present, the resulting sea foam is even more persistent, and can have a chocolate mousse texture.
If the foam forms from the breakdown of a harmful algal bloom (including those caused by some dinoflagellates and cyanobacteria), direct contact with the foam, or inhalation of aerosols derived from the foam as it dries, can cause skin irritations or respiratory discomfort.
On rare occasions large amounts of sea foam up to several metres thick can accumulate at the coast and constitute a physical hazard to beach users, through concealing large rocks and voids, storm debris and, in northern New South Wales, there are even anecdotes of sea snakes.
- A large buildup of sea foam occurred on the coast of Yamba, northern New South Wales, on 24 August 2007, and attracted world-wide media attention.
- Other sea foam occurrences at Caloundra and Point Cartwright, , on Queensland's Sunshine Coast in January–February 2008, also attracted world-wide media attention.
- During live coverage of Hurricane Irene in Ocean City, Maryland, Tucker Barnes was covered in sea foam.
- In December 2011, the coast road at Cleveleys, Lancashire was swamped by metre high drifts of sea foam.
- Following storms and high winds on 24/25 September 2012, the beach front of the Footdee area of Aberdeen was engulfed with sea foam.
- Between 27 and 28 January 2013, the Sunshine Coast in Queensland, Australia, had masses of foam wash up on land from ex-tropical cyclone Oswald.
- June 2016: sea foam across the East coast of Australia, whipped up by storms.
- 28 March 2017: sea foam brought by Cyclone Debbie at Sarina Beach in Queensland, Australia.
- 16 October 2017: Hurricane Ophelia covered Cleveleys, Lancashire with spume.
- 12 December 2017 large amount of sea foam brought by thunderstorm and strong winds to the Ostia beach shore, in Rome. A rare event for the Mediterranean Sea.
- January 2018: Storm Eleanor causes widespread foam across Europe. 
- James G. Acker, What is that foam in the surf? CoastalBC.com. Accessed 5 November 2010
- "It looks like fun but sea foam's full of snakes and disease". Northern Star. Northern Rivers. 24 February 2015. Retrieved 25 July 2017.
- A. Lander, The foam is back!, Sunshine Coast Daily, 20 February 2008. Accessed 5 November 2010
- Sam Benger, Murky foam has residents in lather, Sunshine Coast Daily, 17 January 2008.
- Samantha Williams, Yamba hit by foam lather, The Daily Telegraph, 27 August 2007. Accessed 5 November 2010
- Richard Shears, Cappuccino Coast: The day the Pacific was whipped up into an ocean of froth, Mail Online, 28 August 2007. Accessed 5 November 2010
- Eric Shackle, Australia Foams at the Mouth, OhmyNews, 26 January 2008. Accessed 5 November 2010
- Brett M.Christensen, Whipped Ocean – Beach Foam at Yamba New South Wales, Hoax-Slayer.com, August 2008. Accessed 5 November 2010
- A. Lander, No place like foam Sunshine Coast Daily, 24 January 2008. Accessed 5 November 2010
- Mark Furler, Foam a global hit, Sunshine Coast Daily, 26 January 2008. Accessed 5 November 2010
- "FOX 5's Tucker Barnes Braves the Sea Foam in Ocean City". Fox 5. Archived from the original on January 16, 2012.
- "Sea foam swamps cars at seaside resort of Cleveleys". BBC News. 29 December 2011. Retrieved 30 November 2012.
- "Foam swept in as gales hit Scotland". BBC News. 28 September 2012. Retrieved 30 November 2012.
- "Sunshine Coast Winter Wonderland". Ninemsn. 28 January 2013. Archived from the original on 29 January 2013. Retrieved 28 January 2013.
- "East coast low: Sea foam whipped up by storms could be hazardous to health, toxicologist warns". abc.net.au. 7 June 2016. Retrieved 11 September 2017.
- "Thick sea foam rolls onto Sarina Beach during Cyclone Debbie". abc.net.au. 28 March 2017. Retrieved 11 September 2017.
-  The Independent, 16 October 2017. Retrieved 18 October 2017.
- "Eleanor whips up sea foam party for dog". BBC News. Retrieved 2018-01-04.
|Wikimedia Commons has media related to Sea foam.|
- April 2007 Storm Photo Gallery Lane Memorial Library, Hampton, New Hampshire. Accessed 5 November 2010
- How foam forms on ocean waves Newscientist.com, Issue 1837, 5 September 1992. Article preview. Accessed 5 November 2010
- Blanket of white foam covers Aberdeen coast - Guardian video. Accessed 25 September 2012
- Sea Foam Video on YouTube
- Sea foam covering a swimmer, Australia Gold Coast