Akechi arrived in Beacon on November 1st, 2019. He woke up on the ferry right after he had his fight with the Phantom Thieves. Shortly after his defeat, Shido's cognitive version of Akechi showed up to kill him and the others, stating that once he was done with Akechi, he would take the blame for "the captain" and kill himself. In that moment, Akechi shot the button to separate the group and him. He asked to make a deal with Joker regarding taking down Shido for him.
Upon waking up, he recalled being killed by his cognitive self as he shot him as well. Next to him was a lantern for the dark afterlife he found himself in and a tablet that functioned as a communication device of some sort. He'd spoken to a few people on the ferry, but the ferry stopped for a while before starting up again. When it stopped again, there was no dock to get off on, as it had been destroyed not long before his arrival.
When he finally made it on land, he immediately went to look for answers, finding out more about Beacon and some of the things to expect. What he didn't expect was seeing Akira show up there as well. After a tense, awkward meeting, they two of them set off to have a talk about why Akira was here as well. Akira then informed him about what happened after his death over a cup of coffee.