There will be 18 gyms in Pokémon Sword and Shield - Dot Esports

Split between a minor and major league.

Turns Out Pokémon Sword & Shield Will NOT Have 18 Gyms

The Pokémon Company Clarifies There Are Not 18 Gyms In Sword And Shield - Game Informer

How many gyms will there be in Pokémon Sword and Shield?

Pokémon Sword & Shield will feature 18 gyms, exp share changes, and more - LootPots

Pokemon Sword/Shield to include 18 gyms with major and minor leagues

Pokémon Sword And Shield DLC Causes Notable Spike In Base Game Sales (UK)

Pokemon Scarlet & Violet: All Gym Leaders and their Pokemon types - Dexerto

Galar 18 Gym Leaders by Trainerlouie on DeviantArt

Pokemon Scarlet and Violet Archives - Page 13 of 18 - Dot Esports

The best moveset for Obstagoon in Pokemon Sword and Shield