The facility has been built in place of the old Portobello aquarium which was demolished after it was found to be prone to damage in an earthquake. It was closed to the public in 2012.
The first class is set to be held in the facility next week, after unstable ground conditions delayed its completion by about six months.
Department of marine studies Prof Steve Dawson said the new lab was a "great environment" for teaching and would help address some of the space issues the department had.
The location and view from the lab would help students get excited in marine studies, Prof Dawson said.
"It’s really good to see some vibrancy out at the lab again.
"The teaching space is terrific. It turned out to be much, much better in the flesh than it looked like on the plans."
The department’s space issues were exacerbated by the closure of its aquarium to the public in 2012 after it was found to be less than 15% of the new-building standard for earthquake strength.
The loss of the aquarium was a "great loss" for the department and it was still hoped a new public aquarium would eventually be built in the central city.
However, this was a decision for people "much higher up in the university" than he was.
"It’s a question that does need to be asked, because there is a constant call for it and the old aquarium was surprisingly well used considering it was never exactly flash."
"I think we could do a much, much better job now."
Having a new aquarium would help the department reach out to the public, which was crucial in helping people understand the importance of looking after the world’s marine environment.
"Without healthy seas, we are finished as a species," Prof Dawson said.
The university has placed its plans for building a new aquarium on hold, but the project remains on its books.
Portobello laboratory manager Dr Doug Mackie said the new lab included a 6m display tank which meant "instead of just talking about a fish, you can point to it".
It also housed under cover touch tanks full of sea creatures, which would be used by secondary school pupils during school visits, Dr Mackie said.
A new seawater system pumps 60,000 litres of seawater through the complex every hour - up from 35,000 litres - eliminating the enormous amount of attention staff had to pay to water flows and oxygen levels to keep sea creatures alive.
