The 2018 J1 League, also known as the 2018 Meiji Yasuda J1 League (2018 明治安田生命J1リーグ, 2018 Meiji Yasuda Seimei J1 Rīgu) for sponsorship reasons, was the 26th season of J1 League, the top Japanese professional league for association football clubs, since its establishment in 1992. This was fourth season of J1 League as renamed from J. League Division 1.
The total number of foreign players is restricted to five per club. Clubs can register up to four foreign players for a single match-day squad, of which a maximum of three are allowed from nations outside the Asian Football Confederation (AFC). Players from J.League partner nations (Thailand, Vietnam, Myanmar, Cambodia, Singapore, Indonesia, Malaysia, Iran and Qatar) are exempt from these restrictions.
Players name in bold indicates the player is registered during the mid-season transfer window.