Salmon Days returns for its 46th festival this weekend, Oct. 3-4, but its carnival will kick off the celebration early Friday afternoon — and extend its Friday hours later into the night in anticipation of a repeat of last year’s early attendance surge, festival organizer Brian Twiggs said.

Twiggs introduced the carnival to Salmon Days 2014 amidst an environment of opinion that was unsure whether it would add anything to the festival.

“It was a huge success,” Twiggs said. “For the ‘tweeners … the 10- to 14-year-old crowd, there isn’t a whole lot to do for them at Salmon Days. The carnival gave them a place to go.”

That success earned the carnival a sponsorship from Puget Sound Energy, he added.

The carnival, located in the Staples parking lot at 628 Front St. N., is not expanding its scope beyond last year’s, but it will be the location for a fourth music stage added this year. The stage will be played by student bands coming from the Kaleidoscope School of Music.

Salmon Days is Issaquah’s annual celebration of the return of chinook, coho and sockeye salmon to the Issaquah State Salmon Hatchery on West Sunset Way to spawn. Begun by the Greater Issaquah Chamber of Commerce in 1970 to replace the defunct Labor Day Festival, it remained a minor event centered around its Grande Parade through the decade.

It grew exponentially after being declared a Seafair-sanctioned event in 1980. Salmon Days now includes hundreds of arts, crafts and business vendors, a Food of the World festival, musical performances and a “Field of Fun” play center for young children. Organizers hope to add a beer garden in the future.

Salmon Days brought 180,000 attendees to Issaquah in 2014, Twiggs said.

The carnival opens and runs 3-11 p.m. Friday, runs to 11 p.m. Saturday and 8 p.m. Sunday. Salmon Days kicks off with the Grande Parade on Front Street North at 10 a.m. Saturday. The festival runs 10 a.m. to 6 p.m. Saturday and Sunday.