I'm a 44DD - I usually have problems in tank tops with built-in bras but I found 3 that work, the last has a cute detail

32º DEGREES Cool Womens Shirred Flowly Relaxed Lounge Built-in Cups Shelf Bra Tank Cami, Black, X-Small at Women's Clothing store

Smart & Sexy Everyday Invisitble Full Coverage T-Shirt, Underwire Bras for Women, Bark at Women's Clothing store

HACI Women's Front Closure Bra Underwire Unlined T-Back Plus Size Lacy Unpadded Full Coverage Racerback T-Shirt Bras(Beige,34DD) at Women's Clothing store

20 Best Tank Tops With Built-In Bras For Total Comfort

Women's Lingerie with Push Up Bra Support Everyday Comfort T-Shirt Bra (Beige,34B) at Women's Clothing store

The Shelf Bra Tank is Back and Better Than Ever

Tops with inbuilt Bra Tank Top – Undo Your Bra

Yvette Women High Impact Sports Bras Criss Cross Back Sexy Running Bra for Plus Size, 08A, L(DF) at Women's Clothing store