Heather Watson, Harriet Dart and Katie Boulter all came through qualifying to join fellow Briton Emma Raducanu in the main draw at Indian Wells.
Dart, 25, overcame Russia's Anastasia Gasanova 6-2 3-6 6-3 in a see-sawing match that featured 12 breaks of serve.
Boulter, 25, made more straightforward progress with a 6-3 6-3 victory over Italian veteran Sara Errani.
Earlier Watson came from behind to defeat Japan's Mai Hontama 4-6 6-2 6-1 and secure her place in the main draw.
US Open champion and 11th seed Raducanu has a first-round bye at the event and will face last week's Lyon finalist Dayana Yastremska or France's Caroline Garcia in the second round.
Watson, Dart and Boulter, ranked 113, 122 and 127 in the world respectively, will all need to upset top-50 opposition to join her in the last 64 of the prestigious California event.
Watson takes on the Czech Republic's Tereza Martincova, while Dart will play Croatia's Ana Konjuh and Boulter faces Italy's Jasmine Paolini.
The biggest match of the opening round sees 2018 champion and former world number one Naomi Osaka pitted against 2017 US Open champion Sloane Stephens.
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