BRUNSWICK — Each summer, the Bowdoin International Music Festival hosts more than 100 classical music concerts and recitals. Of those, 17 require a paid ticket. Admission to the rest is free or with a suggested donation.

The festival draws more than 250 of the most promising young musicians in the world, representing 31 countries and 33 U.S. states. Those students, many of whom are enrolled in conservatories to prepare them for careers in music, play dozens of mostly free concerts over five weeks, beginning July 1.

They’ll begin to arrive in Maine in the next few weeks, full of hope and ambition. They’ll immerse themselves in the rigors of intense musical education, with long days of lessons, recitals and performances, while filling the Bowdoin College Quad with the sound of music.

They’ll also get out into surrounding communities, spreading their joy of music to libraries, churches, nursing homes and community centers across the midcoast.

“We like to get them on stage as much as we can,” executive director Peter Simmons said. “Learning how to practice and perform is why they’re here.”

The paid concerts get the attention, and for good reason. The festival brings upper-echelon career musicians to Brunswick to teach and perform. Among the stars on this year’s roster are Frank Huang, who will assume the role of concertmaster of the New York Philharmonic in September; Grammy Award-winning pianist Peter Serkin; and Pulitzer Prize-winning composer Kevin Puts, whom Simmons characterized as “one of the biggest stars we’ve had in years.”

But it’s the musicians without name recognition who provide the most opportunities for music lovers and best embody the festival theme, “The Art of Friendship,” said co-artistic director David Ying.

“The real strength of the festival that has run through time is friendship and mentorship, which is a different aspect of friendship,” Ying said. “Every bit as important as the concerts by the most celebrated guests who come to the festival are the student concerts. They are why the festival exists. At the most un-highlighted student event, that is when you see what the festival is all about.”

This year’s festival includes three concert series that feature student musicians:

n Artists of Tomorrow presents informal solo and chamber performances at 7:30 p.m. Tuesdays and Thursdays – and often on Wednesdays, Fridays and Sundays – at Studzinski Recital Hall on the Bowdoin campus.

n The Extra series involves students and faculty giving concerts, lectures, demonstrations and master classes in and around Brunswick.

n The Community Concerts series dispatches students to perform across the region.

These lower-profile series are the lifeblood of the festival, Simmons said, but are sometimes overlooked by the concertgoing public.

“While most people come to know us first as a concert presenter, we are first and foremost a training ground for the next generation of classical musicians. Our ticketed artists’ concert series are our way of demonstrating to our students the level they need to reach, and a way to provide this great resource to classical music fans in the area,” he said.

The concerts in the festival’s free series provide opportunities for students to practice their lessons, he added. They are scheduled as often as possible, and sometimes several in a day.

The on-campus Artists of Tomorrow concerts are informal and wildly diverse. People sometimes stay for just a few minutes, or for two hours.

The off-campus community concerts help fulfill the festival’s outreach mission, Simmons said. “And the best thing is that these students are really, really good,” Simmons said, “and very enthusiastic about being in Maine and performing to such great, appreciative audiences.”