Introduction This pre-post study explored the effect of children’s 6 months’ experience in one of four early power mobility devices. Method Satisfaction with parent-selected goal achievement was measured using the wheelchair outcome measure for young people and compared with the assessment of learning powered mobility use, as well as device expectation fulfilment ratings. Results Forty-six children with mobility limitations, aged 13–68 months (mean 40.40; SD 15.60) participated. The most common condition was cerebral palsy ( n = 33; 71.74%). The Wilcoxon signed rank test measured the positive change in goal achievement ( z = 4.90; P<0.001; r = 0.51). Fair to good statistically significant Spearman’s correlations were observed between power mobility skill and goal achievement, as well as parent and therapist device expectation scores ( rs = 0.48, 0.46 and 0.66, respectively; P<0.001). Parent and therapist ratings did not differ significantly. No statistically significant associations were found between goal achievement and child (age, diagnosis, abilities) or environmental factors (device, access method, loan length). Conclusion Children at all phases of power mobility skill, using various devices and access methods, can demonstrate activity and participation change following power mobility experience. This study adds validity evidence supporting the use of the wheelchair outcome measure for young people with young children by parent-proxy rating.