Da Nang is spread out enough that walking covers only the immediate riverside centre. Grab (the regional equivalent of Uber) is the most convenient option for getting around — cheaper and more reliable than street taxis. Motorbike taxis (xe ôm) are plentiful for short hops.
Renting a motorbike (around 100,000–150,000 VND/day) gives the most flexibility for reaching the Marble Mountains, My Khe Beach, and the Son Tra Peninsula. The roads are wide and relatively well-marked. Hoi An is 30–45 minutes south by motorbike or around the same by car; day trips by rented motorbike are common.