mossdeep city, to get there, surf east from lilycove also it is a double battle because they are twins
Gym Leaders Tate & Liza
sootopolis city, after u awake rayquaza. the gym leader is juan, changed from ruby/Sapphire Wallace
You have to surf from Lilycove to Mossdeep city so you can challenge the 7th Gym Leader, The psychic twins, Tate and Liza.
If you mean "Is Juan the leader in Pokemon ruby?", then no. It's Wallace who's the leader. Juan is leader only in Pokemon emerald. The champion is Wallace in Emerald, but Steven is the champion is Ruby and Sapphire.
Water, dark and grass Pokemon
Wallace he was the former 8th gym leader in ruby and sapphire
get a pokemon, then you train it, get it really strong, and beat th ecrap out of all the 7th leader's pokemon. Its easy.
To defeat or "beat" the 7th gym leader in Pokemon sapphire there twins and they have a solrock and a lunatone to beat them I suggest about level 40-50 water types.
In Sootopolis City.Trainers and Gym Leader uses Water-Type Pokemon.
Emerald: He is the champion of the Elite Four; Juan is the Sootopolis gym leader. Sapphire/Ruby: He is the gym leader of Sootopolis.
Press the switches to move around the statues and use the portals to the navigate your way to the gym leader's.
Twins Liza and Tate in Moss deep City, they use physicic Pokemon
Go on to defeat the seventh gym in Mossdeep City, if you did not already catch Kyogre.