WASHINGTON—Strong hiring and low unemployment are delivering U.S. workers their best pay raises in nearly a decade.

Employers shook off a September slowdown to add 250,000 jobs to their payrolls in October, above monthly averages in recent years, the Labor Department said Friday. With unemployment holding at 3.7%, a 49-year low, and employers competing for scarce workers, wages increased 3.1% from a year earlier, the biggest year-over-year gain for average hourly earnings since 2009.

“It’s a huge milestone,” Scott Anderson, chief economist at Bank of the West, said of the wage gain. “We’ve finally gotten unemployment low enough that we’re actually getting some traction on wages and salaries. And it looks like we’re pulling more people into the labor force as wages rise.”

The share of Americans in their prime working years, between 25 and 54, who are working or looking for work rose to the highest rate since 2010 last month, at 82.3%.

President Trump touted the figures in a tweet Friday, just days before midterm elections that will decide control of Congress. “Wages UP! These are incredible numbers,” Mr. Trump said.