A navigation channel is set to be closed to marine traffic for three weeks from next month.
It comes as the main, final bascule bridge span of the £145m Gull Wing bridge in Lowestoft is set to arrive from the Netherlands soon.
After there had been delays to delivery of the final phase of the town's long awaited third crossing, Suffolk County Council said a "provisional revised date for the lake closure" had now been confirmed.
As leading building and civil engineering contractor Farrans Construction oversees construction works on behalf of the county council, a Suffolk County Council spokesman said: "We have now agreed a revised provisional date with the Harbour Authority for the temporary suspension of navigation in Lake Lothing for the installation of the main bascule span.
"The lake closure is now provisionally planned to commence on March 8 and will last for three weeks.
"During this time, Lake Lothing will be closed to marine traffic."
It comes as preparations for bringing the bascule section of the bridge across to Lowestoft are "well under way."
As work continues on the bascule section in Westdorpe in the Netherlands, the span will eventually arrive by sea from the Netherlands and enter Lake Lothing through the existing bascule bridge.
A date for the official opening of the bridge - whose total cost was predicted as £145.8million back in 2021 - has yet to be set.
The spokesman added: "Pre-commissioning and installation is the most complex and specialised part of the entire Gull Wing construction to date.
"Our provisional date is subject to final pre-commissioning activities being successful, and suitable weather conditions for both the transportation of the bascule across the North Sea and the installation itself.
"We will therefore provide final confirmation one week before the provisional closure date.
"As well as the most challenging, this will be the most impressive section of all the Gull Wing deliveries and we look forward to sharing with you the arrival of the huge J beams into town when it happens."
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