Swedish climate activist and enfant terrible Greta Thunberg has unveiled plans to spearhead what is being billed as the “Global Sumud Flotilla,” set to depart from Spain on August 31, with additional vessels launching from Tunisia and other Mediterranean ports on September 4. The campaign will involve anti-Israel activists from 44 countries, with participants including figures such as Susan Sarandon, Gustaf Skarsgård, and Liam Cunningham.

“Sumud” is a Palestinian Arabic term that emerged after the 1967 Six-Day War that referred to resistance against “the occupation.”

In a video message, Thunberg and other activists said, “We are sailing again to break the siege, and this time we’re sailing with dozens of boats and coordinated mobilizations from 44 countries around the world.” They claimed the voyage would be “the biggest international solidarity effort ever since Israel implemented its horrific siege 18 years ago.”

Thunberg previously participated in an earlier flotilla mission aboard the vessel Madleen, organized by the Freedom Flotilla Coalition. The ship set sail from Sicily on June 1, 2025 carrying symbolic humanitarian supplies and aimed to deliver aid to Gaza amid the ongoing war. Israeli naval forces intercepted the vessel around June 9, boarded it, detained the activists—including Thunberg—and deported them. Thunberg accused Israel of “kidnapping” her.

The effort was widely criticized as being pointless and described as “a selfie yacht” and  “performative activism”.

International law dictates that vessels attempting to run a declared and lawful blockade may be intercepted and captured, and potentially subject to detainment or seizure of materials. 

In 2010, an attempt by the Mavi Marmara flotilla devolved into a clash between the participants and Israeli forces. When Shayetet 13 commandos boarded the ships, they were attacked on the Mavi Marmara with bludgeons and other weapons. In the fight, 10 flotilla members were killed, and 10 Israeli commandos were injured.