The passenger compartment of the MX-30 remained stable in the offset frontal test. Protection of the passenger dummy was good for all critical body areas. Dummy measurements indicated good protection of the knees and femurs of both the driver and passenger. Mazda demonstrated that a similar level of protection would be provided to occupants of different sizes and to those sitting in different positions. Analysis of the deformed crush element from the offset frontal test indicated that the MX-30's structure did not pose a high risk to the occupants of a colliding vehicle in a frontal offset impact. In the full-width rigid wall test, protection was good or adequate for all body critical body regions for both the driver and the rear seat passenger. In both the side barrier test, representing a collision by another vehicle, and the more severe side pole impact protection of all critical body areas was good, and the car scored maximum points for these two tests. In an assessment of protection in far-side impact, mitigation of dummy excursion (its movement towards the other side of the vehicle) was rated as adequate. The MX-30 is equipped with a centre airbag to protect against occupant-to-occupant interaction in side impacts. This system worked well in Euro NCAP's test, with good protection of the head for both front seat occupants. Tests on the front seats and head restraints demonstrated good protection against whiplash injury in the event of a rear-end collision. A geometric assessment of the rear seats also indicated good whiplash protection. With regard to post-crash safety, the MX-30 has neither an advanced e-Call system nor multi-collision brake.

In both the frontal offset and side barrier tests, protection of both child dummies was good or adequate for all critical parts of the body. The front passenger airbag can be disabled to allow a rearward-facing child restraint to be used in that seating position. Clear information is provided to the driver regarding the status of the airbag and the system was rewarded. One child restraint could not be fitted stably in the centre rear seat. Otherwise, the restraints for which the MX-30 is designed could be properly installed and accommodated.

The protection provided by the bonnet to the head of a struck pedestrian was almost entirely good or adequate. The bumper also provided good protection to pedestrians' legs but protection of the pelvis was mixed. The MX-30's autonomous emergency braking (AEB) system can detect vulnerable road users like pedestrians and cyclists, as well as other vehicles. In Euro NCAP's tests, the system's response to such road users was marginal. The system does not detect pedestrians to the rear of the car, nor those crossing the path of a turning vehicle.

Autonomous emergency braking (AEB) is fitted as standard. The system performed well in tests of its detection and reaction to other vehicles, with impacts being avoided or mitigated in most cases. The MX-30 has a seatbelt reminder for front and rear seats. In addition, the car has a Driver Attention Alert, a system which monitors steering inputs and issues a warning if fatigued or impaired driving is detected. The lane support system gently corrects the steering of the car if it is drifting out of lane and also intervenes much more aggressively in some critical situations. A speed assistance system uses a camera to detect the local speed limit. This information is presented to the driver who can confirm that the car is to be limited to that speed.