Members of the group will camp in central London from Saturday until Tuesday in what they call a “Festival of Resistance”.
It comes after XR activists protested in parliament by supergluing themselves in a chain around the Speaker’s chair.
The protest on Friday, involving around 50 XR members, also saw a person climb scaffolding near Westminster Hall while two others used bike locks to chain themselves to the railings at the New Palace Yard entrance.
The Metropolitan Police made eight arrests and launched an investigation into the incident.
Why is Extinction Rebellion occupying Hyde Park?
XR described the three-day occupation of Hyde Park as “prep” for bigger demonstrations in central London, culminating in 100,000 people taking to the streets next Spring.
The group will meet at Marble Arch on Saturday morning and build the occupying site from the ground up, which will include art and music.
They said they will provide training in community mobilisation and speaking about citizens’ assemblies.
XR says: “The purpose of the occupation is to align thinking around the multiple crises and to ensure that as many people as possible are aware that another model of democracy exists: citizens’ assemblies… and that they could be an answer to our problems.
It adds: “It’s designed to gee-up rebels, upskill them and give them purpose, so that they can head back to their regions empowered and ready to do the hard work that will bring thousands of us to London in October to take mass participation nonviolent direct action.”
What are Extinction Rebellion's demands?
XR wants the government to take action on the climate and ecological crisis and sees protests as the only way of achieving this.
The weekend occupation of Hyde Park is a “first step in a laser-focused, strategic plan” and the group hopes to build up numbers for future demonstrations.
XR has three main demands for the government. They are: telling the truth about the danger the world is in due to climate change, taking urgent action to reduce greenhouse gas emissions to net zero by 2025 and creating a citizens’ assembly on climate and ecological justice.
What have the Met Police and Sadiq Khan said?
The Met Police are facilitating the protest this weekend.
XR said the force agreed to this because it chose "to occupy a green space and focus our attention on nondisruptive, mobilising, educational and community-building activities".
It said it was publicly sharing this plan with the Met to be transparent, but it warned if officers interfered with the protest it would move it to the nearest junction and cause disruption.
The Mayor of London has said he “supports the democratic right to peaceful protest” but stressed they must be done safely and legally.
A spokesperson for Sadiq Khan added: “The mayor supports the democratic right to peaceful protest and it is evident from the extreme weather events London has experienced in recent years that much more needs to be done to tackle the climate emergency.
“However, Sadiq is clear that protests must be carried out safely and lawfully and should not put Londoners or the capital’s economic recovery at risk.
“The Mayor’s top priority is protecting Londoners and he fully supports the Met’s efforts to keep Londoners safe and to keep our city running.”