Pacific Championship Series

The Pacific Championship Series (PCS) is a professional esports league for League of Legends teams competing in the Asia-Pacific. Riot Games, the game's developer, created the league on 19 December 2019. This followed an announcement three months prior by Garena – the game's distributor in Taiwan, Hong Kong, Macau, and Southeast Asia – that it planned to merge the League of Legends Master Series (LMS) and League of Legends SEA Tour (LST) into a single tournament jointly run with Riot Games.

Five teams from Taiwan, one team from Hong Kong, and one team from the Philippines compete in the regular season. The top six teams from the regular season advance to the playoffs and are joined by the top three teams from Japan and the top two teams from Oceania. Oceania became a part of the PCS region on 18 November 2022, with the League of Legends Circuit Oceania (LCO) being downgraded to a tier-two league secondary to the PCS. Japan followed suit the next year on 26 November 2023, with the League of Legends Japan League being similarly downgraded and integrated into the PCS.

Prior to the PCS
The first professional esports league for League of Legends players in Taiwan, Hong Kong, Macau, and Southeast Asia was the Garena Premier League (GPL), which ran from 2012 to mid-2018. Teams from Taiwan, Hong Kong, and Macau were given their own league, the League of Legends Master Series (LMS), in late 2014. Three years later, the Vietnam Championship Series (VCS) was upgraded to a Tier 1 tournament and Vietnam became its own competitive region, separate from the rest of Southeast Asia. The GPL was rebranded as the League of Legends SEA Tour (LST) in mid-2018.

Formation
Garena announced on 25 September 2019 that it intended to merge the LMS and LST into a single league, the details of which would be released near the end of the year. On 19 December, Riot Games announced the name of the new league, the Pacific Championship Series (PCS),  and a list of nine of the ten teams that would compete in it. Berjaya Dragons was announced as the last team joining the PCS on 17 January 2020.

Inaugural season
The 2020 season was postponed until further notice on 29 January due to the COVID-19 outbreak. It was later announced on 18 February that the 2020 season would officially begin on 29 February.

On 13 February it was announced that G-Rex had disbanded its League of Legends team and forfeited its spot in the PCS as a result of internal restructuring by their parent company Emperor Esports Stars. Five days later, Machi Esports was announced as G-Rex's replacement.

Expansion
Riot Games announced on 18 November 2022 that the PCS would expand to include Oceania, beginning in 2023. Two major changes were made: The winners of the League of Legends Circuit Oceania would no longer directly qualify for the Mid-Season Invitational (MSI) and the World Championship (Worlds). Instead, the LCO's top two teams would have to compete in the PCS playoffs to gain a spot. Additionally, LCO players would have their residencies changed from "Oceania" to "PCS", meaning they would no longer take import slots on PCS teams, and vice versa.

On 26 November 2023, Riot Games announced that the League of Legends Japan League would join the PCS playoffs in a similar manner to the LCO. From 2024 onwards, the top three teams from the LJL would have to compete in the PCS playoffs for a spot at MSI and Worlds. Additionally, LJL players would have their residencies changed from "Japan" to "PCS".

Regular season

 * Ten teams
 * Double round-robin, best-of-one
 * Top six teams advance to playoffs

Playoffs

 * Eleven teams: Top six from the PCS regular season, top three from the LJL playoffs, and top two from the LCO playoffs
 * Top two teams from the PCS regular season and the winner of LJL receive a bye to the Stage Two
 * Divided into two stages:
 * Stage One: Eight teams are divided into two groups of four; teams within each group compete in a double-elimination bracket. The three teams consisting of the winners of each group and winner of match between two group runners-up advance to the Stage Two.
 * Stage Two: Six teams compete in a double-elimination bracket.

Qualifications

 * The winner of the spring split qualifies for the Mid-Season Invitational
 * The winner and runner-up of the summer split qualify for the World Championship as the PCS' first and second seeds respectively

Regular-season teams
Ten teams were initially selected by Riot Games as permanent franchise partners of the PCS. However, it was announced on 4 August 2020 that a promotion tournament would be introduced for the 2021 season to promote regional competitiveness.

Taiwan, Hong Kong, the Philippines, and Singapore are currently represented in the PCS regular season; Malaysia and Thailand were previously represented.

By team
denotes a team that no longer competes in the PCS.