The Río Zarumilla, hugging the southwestern edge of Huaquillas, forms the border, and is crossed by the international bridge leading to the small town of Aguas Verdes in Peru. Before crossing it, you’ll need to get your exit stamp at the Ecuadorian immigration office (open 24hr), 2km east of Huaquillas on the road from Machala ($2 by taxi). If you’re coming here straight from Machala, bus drivers will drop you at the office on the way into Huaquillas (remind them as they sometimes forget), but won’t wait for you while you get your exit stamp, usually a fairly fast and painless process. From here, hop on a bus or take a taxi to the bridge, which you’ll have to cross on foot. On the other side, Peruvian officials may check your passport, but entry stamps are normally obtained at the main Peruvian immigration office at Zarumilla, a few kilometres away. It can be reached by mototaxis for about a dollar or by various other forms of transport that continue on to Tumbes, 27km south: regular buses, which won’t wait for you while you get your passport stamped; taxis ($6, including wait at Zarumilla; firm bargaining required); or colectivos (about $0.75), though drivers are sometimes reluctant to wait at Zarumilla. Once in Tumbes, it’s easy to find a direct bus to Piura, Trujillo or Lima.
It’s quite a stressful experience, with a bevy of moneychangers, bus touts, bag carriers and taxi drivers jostling for your business and plenty of thieves around as well – keep your wits about you and never lose sight of your bags. Change as little money as possible, as the rates aren’t good unless you bargain hard. Official moneychangers in Ecuador wear IDs, but always check calculations and cash received before handing anything over.