His arrival comes a day after Morecambe made Donald Love their first summer signing.
The 23-year-old came through the ranks at West Bromwich Albion, spending time on loan at Ross County, Partick Thistle and Lincoln, before signing a permanent deal with the latter in January 2020.
A little more than a year later, the 23-year-old would go out on loan again, this time to Walsall, and also spent time on loan with Stevenage before returning to the Imps.
After signing for the Shrimps, Melbourne told the club website: “I got the news about a week ago that Morecambe were interested.
“I’m excited and looking forward to starting my journey here.
“Being in League One was a big factor for me and, after having conversations with the gaffer (Derek Adams) and Greg (Strong, head of recruitment) about their aspirations and where the club wants to go, I felt like they coincided with my own personal aspirations.
“I’m 23 now, I want to be playing games week in week out because that is how you get the best of yourself. I know that I am going to improve by playing more games.
“My time at Lincoln was a learning experience for me. It was the first time away from West Brom and it was an opportunity for me to go there and improve, learn things and I feel like I can do that here too.
“I want to be able to show people what I can do. I have learned a lot from my time at different clubs, which has helped me playing in different shapes and systems, and I want to bring that experience here.
“I am a versatile defender that has played central, on the left and further forward at times as well.
“I’m naturally a left-back but I want to get forward, get crosses into the box makes things happen, but I’m excited to do the nitty gritty part in defence as well.”