Use this size guide to find the best fitting O'Neill Wetsuit for you. Please contact us if you have any questions regarding the wetsuits or if you require further assistance with sizing.
| Men's | Height | Weight | Chest | Waist | Hips | Neck |
| 2XS | 5'6-5'8 | 115-130lbs | 32.5 - 34.5" | 27-29" | 32-34" | 14 |
| XS | 5'7-5'9 | 125-140 | 34.5 - 35.5 | 28-30 | 33-35 | 14.5 |
| S | 5'8-5'10 | 135-155 | 36.5 - 38.5 | 29-31 | 34-36 | 15 |
| ST | 6'0-6'2 | 145-165 | 36.5 - 38.5 | 29-31 | 34-36 | 15 |
| MS | 5'6.5 - 5'8.5 | 140-160 | 38.5 - 40.5 | 30.5 - 32.5 | 35.5 - 37.5 | 15.5 |
| M | 5'9-5'11 | 150-170 | 38.5 - 40.5 | 30.5 - 32.5 | 35.5 - 37.5 | 15.5 |
| MT | 6'1-6'3 | 160-180 | 38.5 - 40.5 | 30.5 - 32.5 | 35.5 - 37.5 | 15.5 |
| LS | 5'7.5 - 5'9.5 | 160-180 | 40.5 - 42.5 | 32.5 - 34.5 | 37.5 - 39.5 | 16 |
| L | 5'10-6'0 | 170-190 | 40.5 - 42.5 | 32.5 - 34.5 | 37.5 - 39.5 | 16 |
| LT | 6'2-6'4 | 180-200 | 40.5 - 42.5 | 32.5 - 34.5 | 37.5 - 39.5 | 16 |
| XLS | 5'8.5 - 5'10.5 | 180-200 | 42.5 - 44.5 | 34.5 - 36.5 | 39.5 - 41.5 | 16.5 |
| XL | 5'11-6'1 | 190-210 | 42.5 - 44.5 | 34.5 - 36.5 | 39.5 - 41.5 | 16.5 |
| XLT | 6'3.5 - 6'5.5 | 200-220 | 42.5 - 44.5 | 34.5 - 36.5 | 39.5 - 41.5 | 16.5 |
| XXL | 6'0 - 6'2 | 210-230 | 44.5 - 46.5 | 36.5 - 38.5 | 41.5 - 43.5 | 17 |
| 3XL | 6'0-6'3 | 230-250 | 47-49 | 41.5 - 43.5 | 44-46 | 17.25 |
| Men's (Metric) | Height | Weight | Women's (Metric) | Height | Weight | |
| 2XS | 168 - 173 | 50 - 54 | 163 - 168 | 45 - 54 | ||
| XS | 170 -175 | 57 - 64 | 6 | 165 - 170 | 48 - 57 | |
| S | 173 - 178 | 61 - 70 | 8 | 168 - 173 | 50 - 59 | |
| M | 175 - 180 | 68 - 77 | 8S | 164 - 169 | 45 - 54 | |
| MS | 169 - 174 | 64 - 73 | 8T | 171 - 177 | 54 - 64 | |
| MT | 185 - 191 | 73 - 82 | 10 | 170 - 175 | 54 - 64 | |
| L | 178 -183 | 77 - 86 | 10S | 166 - 171 | 50 - 59 | |
| LS | 171 - 177 | 73 - 82 | 10T | 174 - 179 | 59 - 68 | |
| LT | 188 - 193 | 82 - 91 | 12 | 173 - 178 | 59 -68 | |
| XL | 180 -185 | 86 - 95 | 14 | 175 - 180 | 64 - 73 | |
| XLS | 174 - 179 | 82 - 91 | 16 | 180 - 183 | 73 - 82 | |
| 2XL | 183 - 188 | 95 - 104 | ||||
| 3XL | 183 - 191 | 104 - 113 | ||||
| Women's (UK) | Height | Weight | Chest | Waist | Hips | Neck |
| 6 | 5'4 - 5'6 | 100-120 | 30.5 - 32.5 | 23-25 | 33-35 | 11.5 |
| 8 | 5'5-5'7 | 105-125 | 31.5 - 33.5 | 24-26 | 34-36 | 12 |
| 10 | 5'6-5'8 | 110-130 | 32.5 -34.5 | 25-27 | 35-37 | 12.5 |
| 10S | 5'4.5 - 5'6.5 | 105-125 | 32.5 -34.5 | 25-27 | 35-37 | 12.5 |
| 12 | 5'7-5'-9 | 120-140 | 34-36 | 26.5 - 28.5 | 36.5 - 38.5 | 13 |
| 12S | 5'5.5 - 5'7.5 | 115-135 | 34-36 | 26.5 - 28.5 | 36.5 - 38.5 | 13 |
| 14 | 5'8-5'10 | 130-150 | 35.5 - 37.5 | 28-30 | 38-40 | 13.5 |
| 16 | 5'9-5'11 | 140-160 | 37-39 | 29.5 - 31.5 | 39.5 - 41.5 | 14 |
| 18 | 5'11-6'0 | 160-180 | 38.5 - 40.5 | 31-33 | 41.43 | 14.5 |
| Junior's (US) | Height | Weight | Chest | Waist | Hips | Neck |
| 10 | 4’7"-4’10" | 75-90" | 28-30" | 23-25" | 28-30" | 12.5" |
| 12 | 4’10"-5’1" | 90-105 | 29-31 | 25-27 | 30-32 | 13 |
| 14 | 5’1"-5’4" | 105-120 | 31-33 | 27-29 | 32-34 | 13.5 |
| 16 | 5’4"-5’7" | 120-135 | 33-35 | 28-30 | 34-36 | 14 |
| Junior's (Metric) | Height | Weight | ||||
| 10 | 140 - 147 | 34 - 41 | ||||
| 12 | 147 - 155 | 41 - 48 | ||||
| 14 | 155 - 163 | 48 - 54 | ||||
| 16 | 163 - 170 | 54 - 61 | ||||
| Kid's (US) | Height | Weight | Chest | Waist | Hips | Neck |
| 4 | 3’10.5 - 4’1.5 | 40-55" | 23-25" | 20-22" | 23-25" | 10.5" |
| 6 | 4’1.5 - 4’4.5 | 50-65 | 24.5 - 26.5 | 21.5 - 23.5 | 25-27 | 11 |
| 8 | 4’4.5 - 4’7.5 | 60-75 | 26-28 | 23-25 | 27-29 | 11.5 |
| Kid's (Metric) | Height | Weight | ||||
| 4 | 117 - 124 | 16 - 23 | ||||
| 6 | 124 - 132 | 20 - 27 | ||||
| 8 | 132 - 140 | 27 - 34 | ||||
| Toddler's (US) | Height | Weight | Chest | Waist | Hips | Neck |
| 1 | 2’10.5 - 3’1.5" | 25-30" | 19-21" | 18-20" | 19-21" | 9.5" |
| 2 | 3’1.5 - 3’4.5 | 30-35 | 20-22 | 19-21 | 20-22 | 9.75 |
| 3 | 3’4.5 - 3’7.5 | 35-40 | 21-23 | 20-22 | 21-23 | 10 |
| Toddler's (Metric) | Height | Weight | ||||
| 1 | 87.5 - 95 | 11 to 13 | ||||
| 2 | 95 - 102.5 | 13.5 - 16 | ||||
| 3 | 102.5 - 108 | 16 - 18.5 |