On 8 January 1964, the 555th re-emerged at MacDill Air Force Base, Florida as the 555th Tactical Fighter Squadron (555 TFS), operating the McDonnell Douglas F-4C Phantom II.
The squadron was organized from elements of the 557th, 558th and 559 TFS at MacDill, when the parent 12th Tactical Fighter Wing (12 TFW) reduced the number of aircraft from three squadrons of 25 aircraft each to four squadrons of 18 aircraft.

The conflict in Southeast Asia was escalating and throughout 1965 the wing supported Pacific Air Forces (PACAF) Contingency Operations by rotating combat squadrons quarterly to Naha Air Base, Okinawa, in the Ryukyu Islands.
At Naha AB, the squadrons were part of the 51st Fighter Interceptor Wing (51 FIW) and performed as air defense interceptor squadrons for the Ryukyu Islands.
 The 555th had flown its planes to Naha AB in December 1964 on the first three-month rotation.
 Later, the 555th was chosen to return to Naha AB and left MacDill AFB on 6 November 1965 via C-135 Stratolifter transports.
 The 555th relieved the 559th at Naha and assumed control of its F-4 aircraft and other assets.
 The 12 TFW was slated to open Cam Ranh Bay Air Base, South Vietnam (RVN).
 The air defense mission in Okinawa could not be abandoned and a decision was made to keep the 555th there until a replacement unit could be identified.
 The remainder of the 12 TFW deployed to Cam Ranh Bay beginning in November 1965.

An F-102 fighter-interceptor squadron at Hamilton AFB, California was picked to replace the 555th at Naha.
 The F-102 was not able to air refuel, so the F-102s were modified to a U.S. Navy and NATO style probe and drogue refueling configuration and the pilots trained to perform air refueling, a new concept for a fighter-interceptor squadron.
 The F-102s arrived at Naha in late February 1966.
 A decision was made to send the 555th to Udorn Royal Thai Air Force Base (Udorn RTAFB) in North Eastern Thailand, near Vientiane, Laos, and not to join the other three 12th TFW squadrons at Cam Ranh Bay.
Cam Ranh could hold only four F-4C squadrons.
391 TFS had arrived at Cam Ranh awaiting runway construction at Phan Rang.
Until the 391st rejoined 366 TFW, the 12th could not accommodate the 555th (lack of space).
The decision to assign 555th at Udorn was validated in April 1966 when the 555th downed five North Vietnamese Air Force MiG fighters.
 A sixth MiG was downed by an F-4C from DaNang AB, RVN.

Udorn RTAFB was small and when a squadron of USAF F-104As was brought there, it was decided to send two flights, half of the 555th, to Ubon RTAFB.
 There was not enough billeting for the entire 555th at Ubon and what was available was not adequate for daytime rest.
 The 8 TFW was the resident unit at Ubon and were flying only night missions (Night Owl) into North Vietnam.
During the first two weeks at Ubon, the 555th flew day strikes into North Vietnam.
A barracks-type building was hastily constructed to house the entire 555th and the remaining half of the squadron was brought to Ubon in July 1966, at which time the entire squadron began flying Night Owl missions.
 However, the new building was not air conditioned, so the 555th flew from sunset to about 2300 hours local time.
 The two squadrons of the 8 TFW flew the missions from 2300 to sunrise.
 Later in 1966, the 555th was transferred from the 12 TFW to the 8 TFW.

The 8 TFW later became known as the "Wolfpack" and the 555th led the first strike against MiG airfields in North Vietnam.
The 555 TFS launched night bombing attacks against North Vietnam on 29 September 1967.
While at Ubon, the 555th downed additional Migs, including four Mikoyan-Gurevich MiG-21s on 2 January 1967.
The unit thus became the only "Quad Ace" fighter squadron to that point, with 20 MiGs to its credit.

In 1968, the Triple Nickel participated in the campaign against the Ho Chi Minh Trail and the Linebacker campaigns against the North Vietnam heartland in 1972.
During Linebacker I and Linebacker II, the 555th returned to its air superiority role and brought its MiG tally to 39 confirmed victories with ten MiG-17s, thre
On 8 January 1964, the 555th re-emerged at MacDill Air Force Base, Florida as the 555th Tactical Fighter Squadron (555 TFS), operating the McDonnell Douglas F-4C Phantom II. The squadron was organized from elements of the 557th, 558th and 559 TFS at MacDill, when the parent 12th Tactical Fighter Wing (12 TFW) reduced the number of aircraft from three squadrons of 25 aircraft each to four squadrons of 18 aircraft.
The conflict in Southeast Asia was escalating and throughout 1965 the wing supported Pacific Air Forces (PACAF) Contingency Operations by rotating combat squadrons quarterly to Naha Air Base, Okinawa, in the Ryukyu Islands. At Naha AB, the squadrons were part of the 51st Fighter Interceptor Wing (51 FIW) and performed as air defense interceptor squadrons for the Ryukyu Islands.  The 555th had flown its planes to Naha AB in December 1964 on the first three-month rotation.  Later, the 555th was chosen to return to Naha AB and left MacDill AFB on 6 November 1965 via C-135 Stratolifter transports.  The 555th relieved the 559th at Naha and assumed control of its F-4 aircraft and other assets.  The 12 TFW was slated to open Cam Ranh Bay Air Base, South Vietnam (RVN).  The air defense mission in Okinawa could not be abandoned and a decision was made to keep the 555th there until a replacement unit could be identified.  The remainder of the 12 TFW deployed to Cam Ranh Bay beginning in November 1965.
An F-102 fighter-interceptor squadron at Hamilton AFB, California was picked to replace the 555th at Naha.  The F-102 was not able to air refuel, so the F-102s were modified to a U.S. Navy and NATO style probe and drogue refueling configuration and the pilots trained to perform air refueling, a new concept for a fighter-interceptor squadron.  The F-102s arrived at Naha in late February 1966.  A decision was made to send the 555th to Udorn Royal Thai Air Force Base (Udorn RTAFB) in North Eastern Thailand, near Vientiane, Laos, and not to join the other three 12th TFW squadrons at Cam Ranh Bay. Cam Ranh could hold only four F-4C squadrons. 391 TFS had arrived at Cam Ranh awaiting runway construction at Phan Rang. Until the 391st rejoined 366 TFW, the 12th could not accommodate the 555th (lack of space). The decision to assign 555th at Udorn was validated in April 1966 when the 555th downed five North Vietnamese Air Force MiG fighters.  A sixth MiG was downed by an F-4C from DaNang AB, RVN.
Udorn RTAFB was small and when a squadron of USAF F-104As was brought there, it was decided to send two flights, half of the 555th, to Ubon RTAFB.  There was not enough billeting for the entire 555th at Ubon and what was available was not adequate for daytime rest.  The 8 TFW was the resident unit at Ubon and were flying only night missions (Night Owl) into North Vietnam. During the first two weeks at Ubon, the 555th flew day strikes into North Vietnam. A barracks-type building was hastily constructed to house the entire 555th and the remaining half of the squadron was brought to Ubon in July 1966, at which time the entire squadron began flying Night Owl missions.  However, the new building was not air conditioned, so the 555th flew from sunset to about 2300 hours local time.  The two squadrons of the 8 TFW flew the missions from 2300 to sunrise.  Later in 1966, the 555th was transferred from the 12 TFW to the 8 TFW.
The 8 TFW later became known as the "Wolfpack" and the 555th led the first strike against MiG airfields in North Vietnam. The 555 TFS launched night bombing attacks against North Vietnam on 29 September 1967. While at Ubon, the 555th downed additional Migs, including four Mikoyan-Gurevich MiG-21s on 2 January 1967. The unit thus became the only "Quad Ace" fighter squadron to that point, with 20 MiGs to its credit.
In 1968, the Triple Nickel participated in the campaign against the Ho Chi Minh Trail and the Linebacker campaigns against the North Vietnam heartland in 1972. During Linebacker I and Linebacker II, the 555th returned to its air superiority role and brought its MiG tally to 39 confirmed victories with ten MiG-17s, thre
555th Fighter Squadron