When Does Kanji's Social Link Start?

The protagonist can start Kanji's Social Link on June 9th at the earliest, after hearing a rumor that he's bullying students. He can be found during the day on the first floor of the practice building in Yasogami High.

Where do I start Kanji's Social Link?

Kanji's S-Link unlocks automatically as you progress the standard Persona 4 story, but you will have to manually trigger it once unlocked from June 9. On or after June 9, go to the classroom building 2F of Yasogami High. There's a female student here, near one of the sets of stairs.

When can you start Marie Social Link?

You can open the Social Link with Marie any time after April 18th in-game. Just visit the Velvet Room. If there are other events at the same time, you may need to exit and re-enter the Velvet Room - but you will be offered the opportunity to get to know Marie upon entering the Velvet Room after that date.