He knew he was taking a big risk, but is convinced he landed on his feet.
Diame told the Daily Star: "I knew it was risky to leave Wigan. I knew I could get injured or something, but I had to take the chance.
"I was a little bit tired of spending the last day of the season trying to stay up every year and I knew a club would take me.
"I talked with West Ham and they told me about the people they were going to sign. I knew they were going to make their mark on the Premier League.
"I think I made a good choice because I'm very happy at this club. I think we can do something.
"We can finish in the top half of the table. We have stronger players than Wigan, we are more solid and we can score a lot of goals from set plays as well."