The format of EU LCS 2017 has been announced by Riot Games through a (nice-looking) video that you can watch below:

The group draft was done by the head coaches of G2 Esports and H2K-Gaming, the two teams that had the most Championship Points from the last season. After picking the teams that will be placed in the opposing group, Group A had G2 Esports, Fnatic, GIANTS! Gaming, Misfits and ROCCAT; Group B had H2k-Gaming, Origen, Splyce, Vitality and Unicorns of Love.

Teams will face opponents from the same group from Week 1 to 3 and Week 8 to 10. For the remaining weeks, the teams will be going up against the teams in the opposing group. All matches will be best-of-three, and there will be no draws.

As for the playoffs, they will start with quarterfinals where the teams that placed second in their group will be going up against the team that placed third in the opposing group. Then, the winners of the quarterfinals will be going up against the teams that placed first in their group during the Split in the semifinals. The winners of the semifinals will then face each other in the finals for the title of champion.

As for the Promotion/Relegation Tournament, the teams that placed last in their respective groups will be in a Swiss-system tournament with the top two teams from the EU LCS Challenger Series. The teams that get two wins will be promoted to LCS, while those who do not will be relegated.