First Omega Key
Obtained by Smokescreen and Arcee in Egypt from inside a temple. Later they were attacked by Megatron. Optimus Prime fought Megatron in a sword battle for the key. Optimus's sword broke in the process. the key was obtained by Smokescreen and Optimus in the end as they escape from Megatron.
Second Omega Key
Third Omega Key
Fourth Omega Key
Revealed to be inside Smokescreen as the container of the final Omega Key. Captured by Soundwave with assistance from Laserbeak and the Resonance Blaster on the roads in Nevada. It was then extracted by Knock Out via the Phase Shifter. Smokescreen was able to escape with the key that Knock Out took out of him and with the key that was in the Warship's vault. Later, Starscream managed to get they keys from Team Prime and used them as a peace offering to let Megatron welcome him back to the Decepticons. Megatron let Starscream return and the keys were under safe guard.
Battle for the Keys and the destruction of the Omega Lock
Dreadwing gave the Forge of Solus Prime to Team Prime and informed them that the keys were given to Megatron by Starscream. Optimus used the Forge to reconstruct their ground bridge into a space bridge. Team Prime gathered up their weapons and prepared for the fight of their lives. Team Prime faced against the Decepticons on Cybertron to get the keys back and find the Omega Lock. Their plan was starting off well until Megatron used their human friends to trade for the keys. As the Decepticons began using the Omega Lock's power, Optimus had no choice but to destroy the Omega Lock with the Star Saber. The lock and the keys were destroyed in the explosion. When the Omega Lock 2.0 was built under the nemesis, it is unknown if the keys were recreated or not.