Find your fit

Finding the right fit should be simple. Our organic cotton t-shirts are designed for comfort and everyday wear — whether you’re relaxing by the sea, walking on Dartmoor, or just enjoying a slow day at home. Use our size chart below to choose the best fit for you.

Adult Unisex T-Shirt Sizes 

(the female equivalent sizes are giving for information. Please see charts below for measurements)

• XS – 34/36" (UK Size 8)
• S – 36/38" (UK Size 10)
• M – 38/40" (UK Size 12)
• L – 41/43" (UK Size 14)
• XL – 43/45" (UK Size 16)
• 2XL – 46/47" (UK Size 18)
• 3XL – 48/50" (UK Size 20)
• 4XL* – 51/54"
• 5XL* – 55/58"

Not all colours are available in 4XL and 5XL.

How Our T-Shirts Fit

Our tees are a medium fit — not too slim, not too loose. They’re cut to feel comfortable on their own or layered with a hoodie when the sea breeze picks up.

• Soft & breathable: 100% GOTS-certified organic cotton
• Everyday comfort: relaxed enough for downtime, versatile enough for adventure
• True to size: order your usual size for a regular fit, or size up for a looser feel

How to Choose Your Size

👉 If you’re between sizes, we recommend sizing up for extra comfort.

👉 If you prefer a lose or baggy fit we suggest going up a size
👉 Check your favourite t-shirt at home — measure across the chest and compare with our chart.

Why Sizing Matters

At SeaNic, we want every piece to be worn and loved for years. Choosing the right fit helps reduce returns and makes sure your tee feels as good as it looks — sustainable, ethical, and built to last.

SeaNic Size FAQs

Q: Do SeaNic t-shirts come up small or large?
A: Our t-shirts are a standard medium fit. Most customers find their usual size is perfect.

Q: Are larger sizes available?
A: Yes — we stock up to 3XL in most colours, with 4XL and 5XL available in selected colours.

Q: Do SeaNic make women’s and men’s sizes separately?
A: Our t-shirts are unisex, designed for everyone to enjoy. Just use the chest measurement to pick your size.

Size Charts

Adult T-shirts