German paratroopers, the Fallschirmjäger, landed in three areas on 20 May: Maleme, Rethymno and Iraklion. The German operation was a three-pronged strike. The central assault, codenamed Aris, focused on Rethymno. Maleme, on the west of the island, quickly fell.The German 2nd Parachute Rifle Regiment, numbering two battalions and with detachments from divisional support troops, were to land and attack Rethymno. The paratroopers had expected to take the airfield easily, but were surprised when they found it heavily defended.Preceded by heavy aerial bombing, the initial German landing was disorganised, with seven transport Junkers Ju 52s shot down and the paratroopers receiving heavy casualties. However, the paratroopers did manage to capture the hill that 2/1st Battalion was positioned on. German forces were also able to block the roads east and west of Rethymno. On 22 May, after two failed counterattacks, a third counterattack organised in four columns by the Australians drove the Germans off the hill, who took up positions in an old olive oil factory at Stavromenos. While the German paratroopers had no heavy equipment or armour, the Australian troops had the use of two Matilda tanks as well as artillery. However, the two tanks were not used effectively, as both tank crews were originally captured after the tanks were trapped in ditches. Control of one was later regained, and it was used to support the infantry with a further attack by the Australians, which drove the Germans out of the factory on 26 May, who later retreated to Heraklion.Another group of German paratroopers made a landing to the west of the airfield. However, their landings were scattered, and some landed on top of the 2/11th Battalion with others dropping in the nearby plain. Those that were not intercepted or captured moved towards the town of Rethymno itself. Finding Rethymno defended by Cretan police, the Germans took up defensive positions in a ridge that ran from the mountains to the sea.
Realising that Maleme was the key to holding the entire island, the defending force organised for a night counter-attack by two New Zealand battalions, the 20th Battalion of the 4th Brigade and the 28th Maori Battalion of the 5th Brigade. A New Zealand officer present in the battle claims a long delay ordering the planned counterattack turned a night attack into a day attack, which led to its failure. Fears of a sea landing meant that a number of units that could have taken part in the attack were left in place, although this possibility was removed by a strong Royal Navy presence which arrived too late for the plans to be changed.The delayed counter-attack on the airfield did eventually come, but in daylight on 22 May, when the troops were at the mercy of the German Stuka dive bombers, dug-in paratroops, and the newly arrived mountain troops. The attack slowly petered out and failed to retake the airfield. From this point on, the defenders were involved in a series of withdrawals to the eastern end of the island, in an attempt to avoid being out-flanked by the advancing German forces.