LONDON — Saab’s Kockums shipyard is wrapping up the second of two midlife overhauls for Sweden’s Gotland-class submarines, with the second boat going through sea trials now, a company executive said Tuesday.

The air-independent propulsion submarine Gotland was delivered in June with upgrades to the engines, combat system and sensors, many of which will be part of the two-ship A26 program, also under construction at Kockums.

“We signed a contract for these quite brutal midlife upgrades and that was signed four years ago,” said Gunnar Wieslander, head of the shipyard. “The first boat has been delivered by the end of June of this year. Boat No. 2 is now in its sea trial period.

“Boat No. 3 — that has to go through government. The Defence Commission has recommended we do the same with boat No. 3.”

Sweden signed a roughly $163.5 million contract for the two overhauls in 2015, along with another roughly $1 billion for the two A26 submarines.

In an earnings call in July, Saab CEO Hskan Buskhe told investors that Kockums has seen declining revenue as it wraps up the Gotland upgrades, but he was hopeful that will turn around as opportunities open up, including a potential multibillion-dollar contract with the Netherlands to replace its four Walrus-class submarines.

Saab, which is partnering with the Dutch shipbuilder Damen Group, is competing against France’s Naval Group, Navantia of Spain and Germany’s ThyssenKrupp Marine Systems for the Netherlands contract.

But the opportunities for Kockums don’t begin and end with the Netherlands, Wieslander said.

“If you look at a map and at the number of boats out there older than 25 years, you will find that between 50 and almost 90 boats need to be [recapitalized],” he said. “The world is only becoming more open, and the value of operating and being unseen keeps increasing. So we think the relative value of submarines will go up.”