This Seeking Tech guide will explain how you can defeat the Gil Turtle in Final Fantasy V. For this method, make sure you have the Golem summon as well as the following spells:
- Float
- Esuna
- Curaga
- Blizzaga
In terms of your party setup, make sure that two of your characters can Summon. The other two should be able to use Black Magic. You should also make sure that three party members can use White Magic, while the remaining one member is capable of using Time Magic.
Before the fight, make sure you cast Float on your entire. Otherwise, the earthquake attack of the Gil Turtle at the end of the battle may end up wiping out your entire party.
At the beginning of the encounter, summon Golem as soon as possible. Afterwards, make sure you heal your party with Curaga.
Once you have the situation under control, have one character summon Golem and then another character immediately use Blizzaga. You need to alternate between these actions over and over again, only to stop and heal with Caruga and/or Esuna when necessary.
The most important part of this battle is to keep using the Golem summon, as it will block out a vast majority of physical attacks. You should also make sure to recast Float or any party member you got knocked out and then revived.
Eventually, the Gil Turtle will use its earthquake attack when it gets defeated. As long as you have at least one party member with Float, then you should be victorious.