It is time to set sail for new shores, and Playa Flamingo Marina in Costa Rica seems the best place to start. It is the largest marina in the country and a major destination for game fishing. On the menu are wahoo, marlin, tuna and the spectacular sailfish. Purported to be the fastest fish in the water, the creatures have been known to reach speeds of up to 68mph. Can the actor hook the ultimate prize? After being exposed to the elements in Costa Rica, Robson wonders whether he is out of his depth fishing on the open sea. Thankfully, he is aided by two savvy seamen, who teach him some essential tricks of the trade. Trolling slender ballyhoo lures, which zip through the water, they set about trying to attract tuna. It is not long before the crew spots a pod of dolphins – a sure sign that tuna are about Next, it is up to Upala in the north, near the border with Nicaragua, to meet up with some very special anglers. The Club National de Pesca is Costa Rica’s most exclusive fly-fishing organisation. River-angling may be Robson’s domain, but these fishermen use a decidedly more extreme technique After meeting some of the club’s esteemed members, Robson and the group go down to the water’s edge. The actor is appalled to see that the river conditions are less than perfect, as the water is coloured and very deep. But his guides are not deterred, announcing that they will don lifejackets and float down the river, trawling their lines with them. This is a big shock for a man who is used to having his feet planted firmly on the riverbed. But the worst news is yet to come – the men are fishing for machaca, a relative of the piranha... The last leg of Robson’s Costa Rican junket sees him travel to southern Utala to spend some time with an indigenous tribe who rely on fish as their main source of food. The Maleku people teach Robson to use a basic line-fishing method in which fruit provides the bait for some hungrier machaca.

For the second leg of his adventure, Robson heads to the Tennessee river in the Deep South of the US to try 'catfish grabbling'. This perilous sport involves catching giant catfish without using rods.

Robson travels to South Africa, where he finds himself in shark-infested waters while paddle skiing. He also tries his hand at reef fishing in a bid to land the biggest salmon of his career.

Robson is closer to home in this final instalment, but his European fishing trip promises many exotic and varied sporting challenges. First, he is on the hunt for the classic prize of game fishing – the mighty blue marlin. The intrepid seaman’s base is Faial, an island in Portugal’s Azores group. As Robson sets out, clouds gather on the horizon. Will the weather thwart his mission? Next stop is the Canary Islands where Robson attempts to test the limits of his gut by tasting escolar – a snake mackerel found in warm waters around the world. Consumption of escolar is banned in several countries because of its ability to make the eater violently ill as rapidly as half an hour after a meal. The Canary Islanders are big fans of the delicacy. Will Robson share their enthusiasm? The final destination of the series is the River Ebro in Spain, home to the wels catfish. This freshwater monster, which can grow up to ten feet in length, can only be found in European rivers and lakes. Robson is a dab hand at reeling in a 20lb salmon. But how will he fare against one of these beauties, which can be 16 times that size?