running vest with back phone pocket

The 20 × 13cm zipped chest pocket is the phone compartment described for this vest. A dedicated rear phone pocket is not confirmed in the product details available here.

Look closely at the Amazon UK photos if rear storage is a requirement. The two shoulder pockets each measure 10 × 5cm and are not a substitute for a large back compartment.

Front placement can make the phone easier to reach when stopped, while other runners may prefer rear carry. Decide which arrangement suits your routine and choose a product whose listing clearly shows that pocket location.