Traditional pattern, mid-1800s, public domain
A dynamic, undulating design created entirely from half-square triangle units arranged to form alternating waves of color and light. The overall effect mimics rolling ocean swells, requiring hundreds of precisely matched HSTs for a full quilt.
The Ocean Waves pattern originated in the mid-1800s and was particularly popular in coastal communities of the northeastern United States. Its wave-like visual rhythm made it a natural fit for maritime regions, and it appeared frequently in quilts from Maine, Massachusetts, and the Chesapeake Bay area.
Ocean Waves was a favorite scrap quilt pattern, as it uses small triangles that could be cut from any available fabric remnants. The pattern's difficulty lies not in the individual units but in the precise arrangement and assembly of hundreds of half-square triangles to create the flowing wave effect.
Also known as: Ocean Wave, Waves of the Sea, Wave
finished Block Size
14 inches (one repeat unit)
seam Allowance
1/4 inch
grid Basis
2-inch finished half-square triangles arranged in diagonal wave formations
units Required
32 dark/light HSTs and 17 background squares per block unit
All measurements include 1/4" seam allowance unless noted.
| Piece | Fabric | Cut Size | Qty | Notes |
|---|---|---|---|---|
| Dark triangle squares | Assorted dark blues | 3" x 3" | 32 | Pair with light squares for HST construction |
| Light triangle squares | Light blue-white | 3" x 3" | 32 | Pair with dark squares for HST construction |
| Background squares | Light blue-white | 2.5" x 2.5" | 17 | Solid squares for wave troughs |
| Setting triangles | Light blue-white | 5" x 5" | 2 | Cut diagonally twice for side setting triangles |
| Corner setting triangles | Light blue-white | 3.5" x 3.5" | 2 | Cut diagonally once for corner triangles |
Pair each 3-inch dark square with a 3-inch light square, right sides together. Draw a diagonal line on the wrong side of the lighter square. Sew 1/4 inch on each side of the drawn line, cut apart, and press open. Trim each HST to exactly 2.5" x 2.5". Repeat to make 64 HSTs (32 used per block, extras for replacement).
Tip: Chain piece all pairs for efficiency — you can make 64 HSTs in about 20 minutes of sewing.
On a design wall or flat surface, arrange HSTs with the dark triangles oriented to create the wave pattern — dark triangles should form diagonal cascading lines that suggest rolling waves. Place plain background squares in the wave trough positions.
Tip: Take a photo of your layout with a phone — it is easy to accidentally bump pieces out of position.
This block is assembled on the diagonal. Sew HSTs and background squares into diagonal rows, adding side setting triangles at the ends of each row. Press seams in alternating directions for each row so seams will nest.
Tip: Label each diagonal row with a numbered sticky note to maintain correct order.
Sew the diagonal rows together in sequence, matching seam intersections carefully. Add corner setting triangles last. Press row joining seams in one direction.
Tip: Pin at every seam intersection — with this many small pieces, alignment is critical.
Press the completed block from the front. Square to 14.5" x 14.5" including seam allowances. Verify the wave pattern flows correctly and all triangle points are sharp.
Tip: If a few points are slightly buried, the overall wave effect will still read beautifully from a distance.
For the full ocean effect, make multiple blocks and rotate adjacent blocks to create a continuous wave pattern across the quilt top. The waves should flow seamlessly from block to block.
See how this traditional pattern looks in different color combinations.
4x4 block arrangement with continuous flowing wave pattern
Alternating with solid squares for a calmer variation
Single block as a mini quilt with wave-themed quilting