Brendon Hartley set the benchmark time of 1m47.272s early in the one-hour session aboard the #8 Toyota GR010 HYBRID, before Kamui Kobayashi lapped three tenths quicker soon after to record 1m46.954s in the sister #7 car.
That lap time proved to be the fastest of the entire week so far, ahead of Friday’s Sebring 1000 Miles.
Antonio Fuoco’s #50 Ferrari was best of the rest in third, setting 1m48.121s in the closing stages to pip Richard Westbrook in the sole Chip Ganassi Racing Cadillac V-Series.R LMDh, whose 1m48.265s was over a second off the pace of the Toyota duo.
The session was red flagged after 10 minutes, following a clash between Westbrook and Ryan Hardwick’s GTE Am Proton Porsche at Turn 7, which sent the 911 into the tyrewall. That removed 12 minutes from the available running time while the incident was cleared up and was under investigation by the stewards.
James Calado was fifth quickest in the sister Ferrari 499P, which is making its debut in Sebring, ahead of Olivier Pla’s Glickenhaus 007, which was 2.7s off the pace.
The best Porsche Penske Motorsport 963 LMDh was Fred Makowiecki’s #5 car, but it was almost 3s off the pace. The fastest Peugeot 9X8, meanwhile, was slower than the quickest LMP2 car in ninth overall.
A second, much shorter, red flag period was required for Takeshi Kimura's Ferrari spinning to a halt at Turn 3.
In LMP2, Pietro Fittipaldi led the way by setting 1m50.806s in the opening minutes in his #28 JOTA ORECA-Gibson 07, and then extended his advantage with 1m50.326s.
That was almost four tenths clear of the closely matched United Autosports cars, which were just 0.007s apart.
GTE Am proved to be highly competitive with Alessio Picariello (Iron Lynx Porsche 911) leading in the early stages on 1m59.160s, beaten first by Casper Stevenson (D’Station Aston Martin) and then Nicky Catsburg (Corvette) and, eventually, Daniel Serra (Kessel Racing Ferrari 488) who set 1m58.845s.
Third free practice begins at 11:55 local time at Sebring on Thursday.
Sebring 1000 Miles FP2 results:
| Pos | Nº | Driver | Car / Engine | Time | Delay | Laps |
| 1 | 7 | Mike Conway Kamui Kobayashi José María López |
Toyota | 1'46.954 | 25 | |
| 2 | 8 | Sébastien Buemi Brendon Hartley Ryo Hirakawa |
Toyota | 1'47.272 | 0.318 | 24 |
| 3 | 50 | Antonio Fuoco Miguel Molina Nicklas Nielsen |
Ferrari | 1'48.121 | 1.167 | 22 |
| 4 | 2 | Earl Bamber Alex Lynn R.Westbrook |
Cadillac | 1'48.265 | 1.311 | 22 |
| 5 | 51 | A.P.Guidi James Calado A.Giovinazzi |
Ferrari | 1'48.606 | 1.652 | 23 |
| 6 | 708 | Romain Dumas Ryan Briscoe Olivier Pla |
Glickenhaus/Pipo | 1'49.700 | 2.746 | 21 |
| 7 | 5 | Dane Cameron M.Christensen F.Makowiecki |
Porsche | 1'49.782 | 2.828 | 23 |
| 8 | 28 | David H.Hansson P.Fittipaldi Oliver Rasmussen |
ORECA/Gibson | 1'50.326 | 3.372 | 23 |
| 9 | 94 | Loïc Duval Gustavo Menezes Nico Müller |
Peugeot | 1'50.378 | 3.424 | 23 |
| 10 | 22 | Frederick Lubin Phil Hanson F.Albuquerque |
ORECA/Gibson | 1'50.701 | 3.747 | 23 |
| 11 | 23 | Josh Pierson Tom Blomqvist Oliver Jarvis |
ORECA/Gibson | 1'50.708 | 3.754 | 22 |
| 12 | 48 | David Beckmann Yifei Ye Will Stevens |
ORECA/Gibson | 1'50.827 | 3.873 | 24 |
| 13 | 10 | Ryan Cullen Matthias Kaiser Gabriel Aubry |
ORECA/Gibson | 1'50.902 | 3.948 | 21 |
| 14 | 93 | Paul Di Resta Mikkel Jensen Jean-Éric Vergne |
Peugeot | 1'50.914 | 3.960 | 23 |
| 15 | 41 | Rui Andrade Robert Kubica Louis Delétraz |
ORECA/Gibson | 1'50.918 | 3.964 | 23 |
| 16 | 6 | Kévin Estre André Lotterer Laurens Vanthoor |
Porsche | 1'51.060 | 4.106 | 19 |
| 17 | 36 | M.Vaxivière Julien Canal Charles Milesi |
ORECA/Gibson | 1'51.229 | 4.275 | 24 |
| 18 | 35 | André Negrão Memo Rojas Olli Caldwell |
ORECA/Gibson | 1'51.415 | 4.461 | 22 |
| 19 | 4 | Tom Dillmann E.Guerrieri J.Villeneuve |
Vanwall/Gibson | 1'51.524 | 4.570 | 17 |
| 20 | 9 | Filip-Ioan Ugran Bent Viscaal A.Caldarelli |
ORECA/Gibson | 1'51.722 | 4.768 | 23 |
| 21 | 34 | J.Smiechowski Fabio Scherer Albert Costa |
ORECA/Gibson | 1'52.144 | 5.190 | 20 |
| 22 | 63 | Doriane Pin Mirko Bortolotti Daniil Kvyat |
ORECA/Gibson | 1'52.457 | 5.503 | 21 |
| 23 | 31 | Sean Gelael F.Habsburg Robin Frijns |
ORECA/Gibson | 1'52.819 | 5.865 | 12 |
| 24 | 57 | Takeshi Kimura Scott Huffaker Daniel Serra |
Ferrari | 1'58.845 | 11.891 | 20 |
| 25 | 33 | Ben Keating Nicolás Varrone Nicky Catsburg |
Chevrolet | 1'59.122 | 12.168 | 20 |
| 26 | 777 | Satoshi Hoshino Casper Stevenson Tomonobu Fujii |
Aston Martin | 1'59.156 | 12.202 | 22 |
| 27 | 60 | C.Schiavoni Matteo Cressoni A.Picariello |
Porsche | 1'59.160 | 12.206 | 21 |
| 28 | 54 | Thomas Flohr F.Castellacci Davide Rigon |
Ferrari | 1'59.191 | 12.237 | 20 |
| 29 | 86 | Mike Wainwright Riccardo Pera Ben Barker |
Porsche | 1'59.331 | 12.377 | 21 |
| 30 | 21 | S.Costantini Simon Mann Ulysse De Pauw |
Ferrari | 1'59.496 | 12.542 | 21 |
| 31 | 77 | Christian Ried M.O.Pedersen Julien Andlauer |
Porsche | 1'59.506 | 12.552 | 19 |
| 32 | 98 | Paul Dalla Lana Axcil Jefferies Nicki Thiim |
Aston Martin | 1'59.689 | 12.735 | 20 |
| 33 | 83 | L.P.-Companc Lilou Wadoux Alessio Rovera |
Ferrari | 2'00.011 | 13.057 | 22 |
| 34 | 25 | Ahmad Al Harthy Michael Dinan Charlie Eastwood |
Aston Martin | 2'00.041 | 13.087 | 21 |
| 35 | 56 | PJ Hyett Gunnar Jeannette Matteo Cairoli |
Porsche | 2'00.080 | 13.126 | 20 |
| 36 | 85 | Sarah Bovy Michelle Gatting Rahel Frey |
Porsche | 2'00.186 | 13.232 | 19 |
| 37 | 88 | Ryan Hardwick Z.Robichon Harry Tincknell |
Porsche | 2'01.261 | 14.307 | 4 |
