| Final A | Team | time | -time | L | React. | 50m | | 1. Ann Catherine Chandler | --- | 1:07.90 | | 6 | 0.78s | 2. | 32.00s | | 2. Ashley Paige Wanland | --- | 1:08.55 | 0.65s | 5 | | 4. | 33.00s | | 3. Ashley Mcgregor | --- | 1:08.96 | 1.06s | 4 | | 5. | 33.11s | | 4. Alia Atkinson | --- | 1:09.11 | 1.21s | 3 | | 1. | 31.41s | | 5. Kierra Alexandra Smith | --- | 1:10.23 | 2.33s | 2 | 0.81s | 3. | 32.75s | | 6. Tatiane Sakemi | --- | 1:11.46 | 3.56s | 7 | 0.73s | 7. | 33.96s | | 7. Arantxa Medina | --- | 1:12.29 | 4.39s | 1 | | 6. | 33.28s | | 8. Julia Sebastian | --- | 1:12.60 | 4.70s | 8 | 0.86s | 8. | 34.06s |
| Final B | Team | time | -time | L | React. | 50m | | 9. Danielle Beaubrun | --- | 1:10.63 | | 6 | 0.78 | 1. | 32.57 | -. | | 10.Monica Alvarez | --- | 1:12.25 | 1.62 | 2 | 0.70 | 2. | 33.49 | -. | | 11.Daniela Victoria | --- | 1:12.31 | 1.68 | 5 | | 3. | 33.60 | -. | | 12.Mercedes Toledo | --- | 1:12.54 | 1.91 | 3 | | 5. | 34.31 | -. | | 13.Trysha Centeno | --- | 1:12.87 | 2.24 | 4 | 0.72 | 4. | 34.00 | -. | | 14.Isabel Riquelme | --- | 1:13.99 | 3.36 | 1 | | 7. | 34.78 | -. | | 15.Lisa Blackburn | --- | 1:14.75 | 4.12 | 8 | 0.76 | 8. | 35.07 | -. | | 16.Carolina Mussi | --- | 1:15.63 | 5.00 | 7 | | 6. | 34.34 | -. |
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| World record: | | Pan American Games record: |
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| Qualification: | | Standard A: 1:13.3 | | Standard B: 1:15.5 |
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| Heats | Team | time | -time | L | React. | 50m | Heat | | 1. Ashley Mcgregor | --- | 1:09.24 | | 5 | | 2. | 33.56s | Heat 3. | | 2. Ashley Paige Wanland | --- | 1:09.26 | 0.02s | 4 | | 2. | 33.46s | Heat 2. | | 3. Alia Atkinson | --- | 1:09.28 | 0.04s | 5 | 0.77s | 1. | 32.22s | Heat 2. | | 4. Ann Catherine Chandler | --- | 1:09.57 | 0.33s | 4 | 0.80s | 1. | 32.30s | Heat 3. | | 5. Kierra Alexandra Smith | --- | 1:10.15 | 0.91s | 4 | 0.82s | 1. | 33.36s | Heat 1. | | 6. Tatiane Sakemi | --- | 1:12.06 | 2.82s | 3 | | 3. | 34.78s | Heat 2. | | 7. Arantxa Medina | --- | 1:12.79 | 3.55s | 3 | | 6. | 34.78s | Heat 3. | | 8. Julia Sebastian | --- | 1:12.88 | 3.64s | 6 | 0.76s | 4. | 34.36s | Heat 3. | | 9. Trysha Centeno | --- | 1:13.04 | 3.80s | 7 | 0.71s | 3. | 34.18s | Heat 1. | | 10.Daniela Victoria | --- | 1:13.17 | 3.93s | 2 | | 3. | 34.07s | Heat 3. | | 11.Mercedes Toledo | --- | 1:13.20 | 3.96s | 6 | 0.79s | 5. | 34.50s | Heat 1. | | 12.Danielle Beaubrun | --- | 1:13.29 | 4.05s | 3 | | 2. | 33.61s | Heat 1. | | 13.Monica Alvarez | --- | 1:13.36 | 4.12s | 6 | 0.81s | 5. | 35.06s | Heat 2. | | 14.Carolina Mussi | --- | 1:13.75 | 4.51s | 5 | | 4. | 34.27s | Heat 1. | | 15.Isabel Riquelme | --- | 1:13.76 | 4.52s | 1 | 0.75s | 7. | 35.98s | Heat 2. | | 16.Lisa Blackburn | --- | 1:14.33 | 5.09s | 1 | | 5. | 34.75s | Heat 3. | | 17.Mijal Asis | --- | 1:14.71 | 5.47s | 2 | | 6. | 35.31s | Heat 1. | | 18.Patricia Casellas | --- | 1:15.56 | 6.32s | 7 | 0.75s | 6. | 35.33s | Heat 2. | | 19.Alicia Lightbourne | --- | 1:15.66 | 6.42s | 7 | 0.86s | 7. | 35.28s | Heat 3. | | 20.Mckayla Lightbourn | --- | 1:15.95 | 6.71s | 2 | 0.77s | 4. | 34.83s | Heat 2. |
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