Three-point (lap and shoulder) seat belts

Fastening the seat belts: To fasten the seat belts, pull the metal tongue (1) out of the retractor and insert it into the buckle (2). When the tongue latches into the buckle, a distinct "click" will be heard.
The seat belts will automatically adjust their length after the lap portion has been manually adjusted to fit snugly over the hips. If the passenger leans forward slowly to increase slack, the belt will lengthen to allow movement.
However, in the event of sudden braking or a collision, the belt will lock in place. It will also lock if the passenger leans forward too quickly.
NOTE If the seat belt cannot be pulled out of the retractor, pull it firmly outward and release it.
The seat belt can then be pulled out smoothly.

WARNING The lap portion of the belt should be positioned as low as possible and snug around the hips, not the waist. If the lap belt is positioned too high around the waist, it may increase the risk of injury in an accident. Neither arm should be under or over the belt. Rather, one should be over and the other under, as shown in the illustration. Never fasten the seat belt under the arm closest to the door.

When using the center rear seat belt, the buckle marked "CENTER" should be used. (if equipped)

Unfastening the seat belts: The seat belts can be unfastened by pressing the release button (1) on the buckle. After release, the belt should automatically retract back into the retractor.
If this does not happen, check that the belt is not twisted, then try to retract it again.
Test yourself
A quick Kia Rio YB quiz: every answer comes with an explanation and a link to the manual page.