The fire has burnt through 143 hectares of scrub on the edge of the Eyre Peninsula town after starting amid scorching conditions on Thursday.
A fire advice message remains in place but there is no immediate threat to lives or homes.
The Country Fire Service said the blaze was still burning in some spots including the town's rubbish dump and at least six houses and industrial buildings had been impacted.
"Currently thick and potentially hazardous smoke is drifting across the area and the community are urged to limit movement," the CFS said on Friday.
"If at home keep all windows and doors closed,"
Relief fire crews are being deployed to Port Lincoln from across the state.
Milder weather conditions are expected to assist in extinguishing the fire, although the dump is expected to burn for several days.
Local roads closed at the height of the emergency have been reopened but with speed restrictions.
At one stage on Thursday, an emergency warning was in place with some residents warned it was too late to leave.
A local school was evacuated as strong winds fanned the flames.
The dangerous blaze came on the 40th anniversary of Ash Wednesday in South Australia when 28 people died and more than 350 homes were destroyed in major fires in the Adelaide Hills, the Clare Valley and the southeast.
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