On 24 November 3ACS landed near Dulag. The LSTs dropped their ramps in a metre of water and vehicles stalled due to the depth through which they had to pass. A heavy swell made the dozing of approach ramps difficult. Heavy rain was falling making the beach road hard to negotiate, and items of plant bogged down on the beach or the road to the campsite at Vigia Beach, 11 kilometres away. The squadron camp was established on a well-drained sandy site, with the sea on one side and a river on the other. Sanitary arrangements were unsatisfactory and those of the villages in the area extremely primitive   merely a hole under the house. Water was drawn from a water point about five kilometres distance from the camp, and the combination of site, sanitation and provision of water was to have a dramatic effect on the health of the unit. The first sign of a health problem occurred on 29th November when 30 per cent of the unit was affected with ptomaine poisoning for two days. Worse was to come. Pilot Officer McGlashan and 100 men were detailed to load LSTs 734, 911 and 1018 at White Beach, Tacloban, on 1st December. On 4th December the squadron commenced work on the Tanuan strip and assisting with the preparation of a hospital site. Members of the unit also maintained the Tacloban to Dulag access, a single lane macadam road built through coconut groves and on a one and a half metre high embankment through sago palm and rice paddies. This activity was hampered by enemy air activity, the weather, and the requirement to prepare equipment for the Mindoro operation. On 9th December the three LSTs loaded by McGlashan and his party proceeded to Catmen Beach, where they were loaded with the remaining unit equipment. Coconut log ramps were constructed to ease the loading of equipment over'a`bad' beach. A fourth, LST 460, reversed from the beach with only half of its planned consignment of aviation fuel aboard, due to an enormous fire developing in the fuel dump.

The Australians on their LSTs were aware of at least 87 LSTs, Landing Ships Medium (LCM), destroyers, and cruisers in the invasion convoy. It was not an uncontested voyage. The men were at battle stations one hour before dawn, acting as ammunition handlers for the gun crews. Watertight doors were closed and all personnel wore helmets and life jackets. The enemy shore was a mere 13 kilometres away as the convoy, now protected by two battleships, two cruisers, and five aircraft carriers deployed into the Sulu Sea on 13th December. Attacks by enemy aircraft were anticipated. A suicide dive-bomber hit the command cruiser and other suicide aircraft fell to Navy Corsair and Army Lightning fighters. The action continued throughout the night. Next morning the escort carriers launched air strikes and the men could see bombs and shells bursting on the shoreline.
The 3ACS LSTs headed south west through a passage marked in a minefield . Two mines were sighted and exploded en route before the LSTs were in position for the run into the beach next morning. Shellfire on the beach and enemy air activity added to the tension. Breakfast was at 4am. At dawn the men could see Mindoro dead ahead, the red roof and black stack of the San Jose sugar mill standing out behind the beach markers. Enemy aircraft attempted to harass the landing, but met accurate antiaircraft fire. As the infantry landed and penetrated inland enemy aircraft were sighted overhead. Five were shot down by anti aircraft fire. Two LSTs were hit by diving suicide bombers as 3ACS landed on White Beach at 8.45 am on 15th December.

The unit was the first to unload, but, according to the Filipinos they were late the landing had been expected on the 12th. Without delay, the surveyors established the centre line for airfield `A2'. The squadron, disorganised by lack of communications and with plant spread out or bogged on the route to its allocated campsite, established a temporary overnight bivouac. Half hourly enemy raids continued throughout the night. Next morning the squadron moved to its permanent campsite.

The squadron commenced work on the `A2' taxiway on 16 December. It was a day of high drama. A suicide bomber in Magarin Bay hit the command cruiser. Casualties were heavy. Colonel Hill, the Task Force Chief of Staff was killed one of 350 casualties. 3ACS also suffered its first casualties. Leading Aircraftman W.E. Barham was killed by debris from a suicide plane, which attempted to dive through the open doors of an LST on Red Beach, and Leading Aircraftman P. Cutajar suffered from petrol burns in the same incident.

3ACS combined with the 866th and 1874th Aviation Engineer Battalions to construct the `A2' airfield (now named Hill Field) near San Jose. Work commenced on the main runway on 17th December. Three days later 15 Dakotas landed on the airfield, confirming the urgency of the requirement. This was also reflected in the shifts worked   only two and a half hours each day were allocated as non productive.

The defending Japanese did not abide by the invader's plans. During daylight hours the beachhead was under constant threat from enemy aircraft and surface units. Overhead the P 38 Lightnings, P 47 Thunderbolts, and Navy Corsairs countered the incursion of Japanese fighters and suicide bombers. Squadron Leader A. Overland has left a graphic account of one dogfight. On 20 December he records that there was.
Shipping losses could not be prevented. On 22 December, for example, LST 749 was sunk with the loss of a quarter of the strength of the American 340th Engineer Aviation Battalion. 6 Flight Lieutenant O'Brien and his detachment were aboard LST 460, which was also sunk. There were no Australian casualties. The daylight hours were filled with the noise and vision of the exploding anti aircraft shells, the whine of supercharged aero engines, and the death dives of aircraft, burning and mutilated ships, and tension.
The enemy air activity had material effect on the night of 3rd January 1945. A bomb penetrated into the soil of one of the aircraft inserts before exploding, leaving a crater 13 metres in diameter and six metres deep. Clods of earth were found on aircraft parked hundreds of metres from the explosion. Of the three aircraft in the insert, one was smashed to smithereens; the second crumpled `like a concertina and the third only slightly damaged'. The confusion of the night made it dangerous for friendly aircraft as well. On the night of 1st January Wing Commander Rooney was a passenger on a C46 Commando, which was illuminated by a searchlight and fired upon. The pilot decided to circle until his aircraft could be positively recognised in daylight. Unbeknown to him, the C 46 `spent the hour circling around nearby gullies which ... comprised the main route in and out for enemy aircraft ... The C 46 was caught in an ever rising, ever narrowing gulch.' The pilot ordered equipment to be jettisoned to enable the aircraft to climb to safety. If Japanese air strikes were a tangible threat, the reports of potential Japanese parachute landings had an insidious effect on the troops. As part of the second defence line, members of the squadron manned a perimeter of 2,285 metres on a 24 hour basis.

The defensive perimeter was linked by telephone with the American 19th Regimental Combat Team. Coincident with the report of lights and fires being lit in the hills (interpreted as signals for a possible parachutist landing) this link was broken on the night of 17th December. Although the incidents were not related the tension was so evident that 3ACS considered that it was `not possible to send men over [to 19 Regimental Combat Team] as guards would shoot'. A walkie talkie radio was borrowed to augment the communications between the two units. Another alert was sounded on the night of the 20th, resulting in considerable confusion and a `sincere exhortation from Squadron Leader Bouch urging his men to use their bayonets and cut the throat of the bastards'. The potential for suicide attacks by Japanese parachutists was real; groups had landed on the Leyte airfields and caused considerable damage to aircraft and facilities.
The potential threat of paratroop landings often based on unsubstantiated rumour, doubt, and uncertainty had a psychological effect on the troops. A Japanese naval foray was a matter of fact, not rumour. At 6.55 pm, 26th December 1944, the warning of the approach of a Japanese fleet activated the defence plan. The `Green' defensive line was manned. At 8.00 pm orders were received at 3ACS to evacuate the camp area. Action was expected within the hour. For the men there was a confusion of reports and visual impressions. Bombs dropped by Japanese aircraft burst along the beachhead against a background of tracer bullets and the lights of fighters attempting to intercept aerial intruders. Fourteen kilometres to seaward, naval Patrol Torpedo Boats sortie to attack the approaching Japanese warships. Hill Field, became the target of the Japanese heavy guns. Star shells burst over the strip and campsite, which was also subjected to the attention of enemy bombers. Two unexploded bombs were later discovered between the tents and dealt with by the Bomb Disposal Unit. The men, huddled in their gun posts could feel the reverberation of heavy shells striking nearby, and see star shells illuminating the sky over San Jose. Squadron Leader Overland understated the situation when he recorded that `the whole evening performance is developing into quite an alarming affair'.

Personnel of 3ACS remained at readiness until 5.30am. For the men huddled in cold defensive positions, unaware of the overall situation, it had been an anxious night. Those men who had volunteered to transport ammunition and bombs to the San Jose airfield and troops from the Blue Beach to battle stations during the bombardment had many narrow escapes. The night shift operators, aware that the airfield would be required to be operational by dawn, displayed courage and fortitude by standing by at the airstrip during the shelling. In the light of day the impact of the enemy activity could be assessed. Although a liberty ship had been lost, damage to the facilities ashore was negligible. The raid had little effect on the activities of 3ACS. Fatigued but unbowed, the men continued   it was another day at the office.