They gathered on Sandymount Strand on the southside to voice their opposition to plans by Providence Resources to begin exploration work 6km off the Dublin coast.
The protesters donned white overalls and carried bath cleaning equipment to show the kind of clean up they claim might have to take place if there was an oil leak.
The group included United Left Alliance TD Richard Boyd Barrett and councillors Melisa Halpin and Hugh Lewis.
Ms Halpin, of the People Before Profit group, said dozens of people came together on the beach to highlight their concerns.
She told the Herald that they wanted "to highlight the potential dangers of putting an oil rig in Dublin Bay".
"We were showing what it would be like if there was a spillage -- the clean up and the mess that would be involved," Ms Halpin added.
She denied that it was sensationalist, saying wherever there is an oil rig there is a risk of a spillage. "You should not drill that close to shore. There is always the threat of contamination," she added.
Because of the way the tides run in Dublin Bay, if there was a leak it would "contaminate the whole bay within hours," she added.
Save Our Seafront gathered at the Martello Tower in Sandymount to illustrate the potential dangers of oil exploration in Dublin Bay, they said.
Providence Resources has received an exploration and a foreshore licence to explore the potential of a prospect approximately 6km off the Dublin coast in the Kish Bank Basin, at Dalkey Island.
It says a seismic survey is a vital investigation ahead of any drilling.
"Rigorous environmental and health and safety standards form a vital part of the company's ethos," the company said. It has argued the project would be of significant economic benefit to Ireland, with up to 40pc of profits from production accruing to the State.
The Save Our Seafront group has been working with others in opposition to the plan.
The issue of the foreshore licence is the subject of a judicial review that An Taisce is bringing to the High Court in February.
An Taisce claims by holding no Environmental Impact Assessment (EIA) was required before awarding the licence, the Government has acted unlawfully. It says the decision to grant the licence should be quashed as an EIA was required under an EU directive.