Outdoor Physical activity offers many health and well-being benefits for older adults, yet, participation is often constrained by environmental, physical, and social barriers. Technology has the potential to support engagement, but current designs rarely incorporate perspectives from both older adults and experts in the field of Physical activity. This study explores design considerations of technology to promote outdoor PA by triangulating the insights of older adults and experts. We conducted semi-structured interviews with 11 Physical activity experts and 4 focus group workshops with 24 older adults. Data were analysed using thematic analysis and grounded-theory coding. Triangulation was used to identify divergent, convergent perspectives, and complementary views between groups. Our findings identified shared priorities around social engagement, environmental accessibility, and family, together with divergences about risk management versus independence, conceptualisation of support, and clinical benchmarks versus personal enjoyment. And complementary views around personalisation and flexibility. Based on the findings, we developed design considerations that emphasise embedding emotional and social value alongside clinical goals, supporting autonomy while ensuring safety, and incorporating intergenerational activities. These design considerations translate into practical implications, including accessible features such as mood and movement based music activation, selective safety modes with on-demand location sharing, and low-barrier intergenerational story trails that can be implemented in future outdoor PA technologies