* Lithuania lobbying for decoupling date in 2024

* Estonia PM says it will happen in 2025

* Three Baltic countries must move at same time

(Adds Lithuania grid operator says will continue to lobby for earlier decoupling, paragraphs 6-7; Adds bullet points; Edits)

VILNIUS, July 17 (Reuters) - The Baltic states are set to decouple from the Russian power grid in early 2025 despite calls from Lithuania for an earlier exit, Estonian Prime Minister told Reuters.

Three decades after splitting from the former Soviet Union and 19 years since joining the European Union, the Baltic states of Estonia, Latvia and Lithuania still depend on Russia to ensure a stable power system.

Lithuania has been arguing for a decoupling date of early 2024, saying that Russia is undependable and an aggressor. But this is not acceptable to Estonia, which would bear the brunt of the cost of an earlier move, Estonian Prime Minister Kaja Kallas told Reuters.

"I understand that Lithuania wants to have it faster, but the question is that ... Estonia would pay the highest price for this in terms of the (cost), but also in terms of risks of blackouts," said Kallas, speaking on the sidelines of NATO summit in Vilnius last week.

"As a compromise, we're agreeing to bring this deadline a year closer. So, leaving in the beginning of 2025," Kallas said.

Lithuanian power grid operator Litgrid said it would continue to lobby Estonia and Latvia to move sooner, but it will follow Estonia's timetable if Estonia holds firm, because all three Baltic countries must decouple together.

"We are dependant on Estonia, so if they don't change their mind, sadly, it will happen according to their timetable (in early 2025)" said Rokas Masiulis, the chief of the Lithuanian power grid operator Litgrid, in comments made to Lithuania's public radio on Monday.

"We see what happens in Ukraine, where people are being killed and bombs continue to fall – I don't think it's the right choice to keep cooperating with the aggressor just because this saves a few cents," Masiulis told reporters on Monday.

Under a deal signed in 2018, the leaders of the region, with support from Poland and the European Commission and 1.6 billion euros ($1.61 billion) in European funding, agreed to upgrade their infrastructure and disconnect from the Russian grid by 2025.

The decoupling will be announced by a formal application to the Baltic, Russian and Belarus joint grid operators in August 2024, Kallas said. (Reporting by Andrius Sytas in Vilnius; Editing by David Evans and Conor Humphries)