Thermos Sipp 16-Ounce Leak Proof Drink Bottle with Tea Infuser, Stainless Steel Review (2026)

Who this bottle fits

The Sipp is built for someone who wants a dependable, leak resistant bottle for loose leaf tea on a commute, at a desk, or on errands, and who values a locking lid over a simple flip top. At 16 ounces it sits between a compact tea tumbler and a larger all day flask, enough for a solid single serving plus a bit more without being bulky in a bag. Buyers who already trust Thermos for insulated drinkware, or who have dealt with leaks from looser fitting lids on other bottles, are the clearest fit here. It is less suited to someone who wants maximum capacity for a full day out, since 16 ounces will need a refill sooner than a taller bottle.

Design and the locking lid

This bottle uses double wall stainless steel construction with Thermos vacuum insulation, which is built to keep drinks hot for around 12 hours or cold for around 24 hours by creating an airless gap between the inner and outer steel walls. The standout feature is a locking, leak proof lid that opens and closes with the push of a button, made from BPA free Eastman Tritan copolymer chosen for stain resistance and durability. Integrated tea hooks inside the bottle let loose leaf tea steep directly in the body without a separate removable basket, and the double wall insulation keeps the exterior cool to the touch with hot drinks and free of condensation with cold ones.

Living with it day to day

Because the tea hooks are built into the bottle rather than a removable infuser, there is no separate strainer part to keep track of or misplace, which simplifies daily use compared with bottles that use a lift out basket. The push button locking lid takes a bit of getting used to compared with a simple flip top, but it is the feature that makes this bottle noticeably more leak resistant for a bag or backpack. Thermos lists the lid as top rack dishwasher safe, which is a plus for anyone who wants to skip hand washing the mechanism after every use, though hand washing the hook area may help it stay effective longer.

Trade-offs and how it compares

Against the MIRA 18 oz Tea Infuser Thermo, the Sipp holds two ounces less but trades MIRA's removable two piece strainer for fixed tea hooks and a locking push button lid rather than a flip top, a meaningful difference for anyone who leaks concerns matter to more than infuser flexibility. Against the Zojirushi One-Touch mug, the Sipp's locking lid design is closer in spirit, though Zojirushi's one touch opening trades a small amount of leak resistance for faster one handed sipping. Shoppers who want the most leak resistant lid in this group should lean toward the Sipp's locking design over a flip top or one touch mechanism.

Verdict and who should pick something else

Pick the Thermos Sipp if a leak resistant, locking lid matters more to you than maximum capacity or a removable strainer, and 16 ounces covers your typical outing. It is a strong choice for commuters and bag carriers who have been burned by looser fitting lids before. Skip it if you want a full 18 to 22 ounce bottle for a longer day, or if you would rather have a removable strainer like MIRA's so the same bottle can double as a plain water thermos. Those who prefer one touch opening over a push button lock may also prefer a different mechanism.

Frequently asked questions