Is there a third part of Gundam Seed?

There is no third part. "Mobile Suit Gundam SEED" is an animation released in the Gundam series from 2002 to 2003. The sequel was broadcast in 2004 as "Mobile Suit Gundam SEED DESTINY".

Because of its charming characters, star-studded voice actor lineup and exciting and fierce battle scenes, it is deeply loved by the majority of anime fans. Different from the previous focus on the psychological description of war, this drama uses a large number of plots to describe the emotional entanglements between several protagonists, thus attracting a group of fans who have never watched Gundam, triggering drastic changes in the Gundam series.

Extended information:

Gundam seed plot synopsis:

The new human being "COORDINATOR" living on an artificial satellite has begun to recognize the world decades later …

C.E.70.02.11

Earth United and Z.A.F.T. are in a stalemate due to economic conflicts. The two are trying to resolve the dispute through diplomatic means, but various problems have arisen. The two parties were stuck in a fork in the road, and finally declared war.

The war and peace between the two factions turned into an outright war after the so-called "Bloody Valentine's Day" incident. During Valentine's Day, humans used nuclear bombs to attack the satellites of the New Humanity, causing a large number of casualties. The all-out war between the two forces directly led to the occurrence of some incidents, such as dragging a third-party neutral force into the battle, and also involving some teenagers in the vortex of the war.

Kira Yamato is a student at the Industrial University. He was a very good friend with Aslan, the son of Speaker Sara, the most powerful person in the new human forces. After Aslan returned to the country, Kira Live a peaceful life.

Until one day when I went to school with a group of friends, I encountered the ZAFT army coming to snatch the Gundam. Kira was able to enter the Gundam and start piloting the Gundam. Battle Orchid

Reference material Baidu Encyclopedia—Mobile Suit Gundam Seed