Looking for a plastic straw to sip your soda?
Businesses that don't comply with the ban can now face a $250 fine.
The ban impacts over 5,000 restaurants and food providers in the region.
As the threats posed by plastic straws, utensils and other small plastic items have become clearer, environmental groups have made a broad push for cities to curtail their use through legislation.
Restaurants were encouraged to use up existing supplies of plastic straws and utensils before July.
This ban comes a decade after the city first adopted an ordinance in 2008 to require that all one-time-use food service items be recyclable or compostable.
"Plastic pollution is surpassing crisis levels in the world's oceans, and I'm proud Seattle is leading the way and setting an example for the nation by enacting a plastic straw ban", Seattle Public Utilities General Manager Mami Hara said in a statement last month. Maybe you've seen that video of the sea turtle with a plastic straw lodged in its nostril, or read about the whale that died after eating a plastic DVD case. Then, the products were "30 to 40 percent more expensive", he said.
California's Legislature is considering statewide restrictions, but not an outright ban, on single-use plastic straws.
Every day, people in the USA use and discard an estimated 50 million straws.
The ban came into effect Sunday-and isn't just limited to straws. Seattle Public Utilities exempted plastic utensils and straws due to a lack of compostable alternatives.