Shell to Sea (Irish: Shell chun Sáile) is an Irish organisation based in the parish of Kilcommon in Erris, Ireland. It opposes the proposed construction of a natural gas pipeline through the parish, as well as the ongoing construction—by Royal Dutch Shell, Statoil, and Vermilion Energy Trust—of a refinery at Bellanaboy near Belmullet, Ireland intended to refine the natural gas from the Corrib gas field. It proposes the gas be refined at sea, rather than inland, as is done with Ireland's only other producing gas field off County Cork. Shell to Sea believes the proximity of a raw natural gas pipeline is a risk to local residents.

The three aims of the campaign, as cited on its website, are as follows.

Incidents of note include the 2005 jailing of the Rossport Five and the public outcry which ensued, the 2007 Goldman Environmental Prize received by Willie Corduff (one of the five), local fisherman Pat O'Donnell's laying of 800 crab pots at sea, Maura Harrington's hunger strike against the Allseas pipe-laying ship Solitaire in 2008, an alleged assault on Corduff in 2009 which was condemned by Desmond Tutu, the 2011 "rape tape" scandal when Gardaí (police) accidentally filmed themselves joking about the imagined rape of two female protestors after arresting them, and the reports of gifts of alcohol worth tens of thousands of euros from Shell to the Gardaí, which broke in 2013.

Opposition to the gas consortium and government's plans among local residents grew from 2000 when local residents felt they were not adequately consulted. They opposed planning permission and appealed it to An Bord Pleanála twice. It was felt that government pressure was used to force the planning permission through. They felt misled about the safety of the gas pipeline which did not require planning permission under the 1976 Gas Act.

The first event organised by Shell to Sea was on the June Bank Holiday weekend in 2005 in support of Rossport residents' protests. Local landowners in Rossport had previously been told that the raw gas pipeline would be coming through their lands no matter what, and that they would be subject to Compulsory Acquisition Orders if unwilling to reach a deal with Shell. Some agreed to allow Shell on their lands. Others refused and Frank Fahey, the Minister for the Marine and Natural Resources, signed 34 Compulsory Acquisition Orders. Those who had refused were threatened with legal action. Legal action was taken which eventually culminated in four farmers and their former teacher, who had joined them in blocking Shell workers coming on their lands, being jailed on 29 June for civil contempt of court (at the request of Shell) after refusing to give an undertaking not to interfere with Shell's workers. They became known as the Rossport Five.

Round the clock pickets on the Shell sites at Rossport, Bellanaboy, and Glengad began after the protesters' jailing. Rallies in support of the men's stance were held in major towns and cities; Shell and Statoil filling stations were picketed. From the protests emerged the national Shell to Sea campaign.

The Rossport Five were released on 30 September, after their imprisonment had dominated proceedings in the parliament. Peter Cassells was appointed as a negotiator to arbitrate between the campaigners and Shell. As his remit did not include discussing the refinery, he was regarded as a distraction by Shell to Sea. The pickets at Bellanaboy continued for over a year, during which no work was done by Shell.

On Tuesday 26 September 2006, protesters prevented Shell's employees from entering the site of the intended refinery at Bellanaboy to begin work. Around 150 locals and protesters blocked the entrance to the refinery site and began to recite the rosary. The workers turned back^{[citation needed]} after discussions with Gardaí.^{[citation needed]}