Mason Lake Fish Stocking
King County, Washington · 1995–2023 on record
According to Washington fish & wildlife agency, Mason Lake was last stocked September 7, 2023 with Rainbow Trout. Mason Lake has 13 stocking records on file, spanning 1995–2023, with about 8,833 fish stocked over that period.
When Mason Lake is stocked
Mason Lake is typically stocked in summer and fall, most often in August — 4 stocking events in that peak month.
By species
Angler's Field Guide
Fishing Tips & Stocking Guide for Mason Lake
Practical advice on fish behavior, recommended tackle, and state regulations for anglers fishing in King County, Washington.
Post-Plant Behavior & Timing
Hatchery-raised fish are conditioned to pelleted feed and open raceways. Following a release into Mason Lake, they typically congregate in schools near public access points, boat ramps, or inlets for the first 24 to 48 hours while adjusting to natural water conditions.
Since Mason Lake was last stocked September 7, 2023, anglers visiting within 1 to 2 weeks of a reported event generally experience the highest activity before fish disperse into deeper cover.
State Regulations & Licensing
- •Fishing License: A valid Washington freshwater fishing license is required for anglers age 16 and older.Purchase Washington license online →
- •Official Rules & Limits: Bag limits, bait restrictions, and seasonal boundaries are set by Washington fish & wildlife agency.Official Washington regulations guidebook →
- •Ethical Conservation: Use barbless hooks and keep fish submerged in water during unhooking.Trout Thermal Advisory: When water temperatures rise above 68°F (20°C), released trout face severe mortality from thermal exhaustion. Target warmwater species or fish early in the morning when lakes and streams warm up.
Recommended Tackle & Presentations
Techniques tailored to the species stocked in Mason Lake:
Stocked Trout Tactics
Use light 4–6 lb monofilament or fluorocarbon line. Float scented dough bait (PowerBait) 12–18" off bottom using a sliding slip-sinker rig with a size 14–16 treble hook. For active casting, throw 1/16 to 1/8 oz inline spinners (Panther Martin, Rooster Tail) or small spoons (Kastmaster) along drop-offs.
Rainbow Trout Profile Tips
The most commonly targeted stocked trout in the country, taken on bait, spinners, and flies alike; a common first fish for new anglers.
Recommended Tackle for Mason Lake
Field-tested tackle and presentations matched to the species stocked here.
Berkley PowerBait Floating Trout Dough
Hatchery-raised trout are conditioned to pelleted scents; scented dough floated 12–18 inches off bottom consistently triggers strikes.
Panther Martin Classic Teardrop Inline Spinner
The heavy convex blade spins instantly upon retrieval, sending vibration through the water that triggers aggressive reaction bites along drop-offs.
Sliding Sinker & Treble Hook Rigging Kit
Sliding egg sinkers allow cautious trout to run with bait without feeling line drag, while size 14–16 treble hooks keep dough bait securely pinned.
As an Amazon Associate, StockedWaters earns from qualifying purchases at no additional cost to you. Recommendations are chosen for hatchery-conditioned fish behavior and ethical rigging. We may receive a referral commission if you buy through these links. Read our editorial policy & standards.
Nearby stocked waters
Other stocked waters near Mason Lake, freshest activity first.
Windy Lake
3 miKing County · 1 species · 6 records
Last stocked September 2025
Island Lake
1 miKing County · 1 species · 11 records
Last stocked September 2025
Lake Caroline
5 miKing County · 1 species · 5 records
Last stocked September 2025
Rainbow Lake
1 miKing County · 1 species · 30 records
Last stocked July 2025
Kulla Kulla Lake
1 miKing County · 1 species · 9 records
Last stocked June 2025
My Lake
3 miKing County · 2 species · 9 records
Last stocked October 2024
Stocking history
Most recent stockings first. Dates shown at the precision the agency reported.
| Date | Species | Number | Source |
|---|---|---|---|
| September 7, 2023 | Rainbow Trout | 820 | Washington fish & wildlife agency |
| August 15, 2020 | Rainbow Trout | 820 | Washington fish & wildlife agency |
| June 29, 2017 | Rainbow Trout | 800 | Washington fish & wildlife agency |
| August 5, 2014 | Rainbow Trout | 408 | Washington fish & wildlife agency |
| October 18, 2010 | Rainbow Trout | 425 | Washington fish & wildlife agency |
| July 22, 2010 | Rainbow Trout | 390 | Washington fish & wildlife agency |
| March 6, 2007 | Rainbow Trout | 390 | Washington fish & wildlife agency |
| March 5, 2007 | Rainbow Trout | 390 | Washington fish & wildlife agency |
Show 5 more stocking records →
| Date | Species | Number | Source |
|---|---|---|---|
| August 17, 2004 | Rainbow Trout | 780 | Washington fish & wildlife agency |
| September 18, 2003 | Rainbow Trout | 1,750 | Washington fish & wildlife agency |
| September 19, 2001 | Rainbow Trout | 750 | Washington fish & wildlife agency |
| August 18, 2000 | Rainbow Trout | 325 | Washington fish & wildlife agency |
| September 11, 1995 | Rainbow Trout | 785 | Washington fish & wildlife agency |
The reporting agency did not include fish sizes for this water.
Frequently asked
When was Mason Lake last stocked?
According to Washington fish & wildlife agency, Mason Lake was last stocked September 7, 2023 with Rainbow Trout.
What fish species are stocked in Mason Lake?
Mason Lake is stocked with Rainbow Trout.
What time of year is Mason Lake stocked?
Mason Lake is typically stocked in summer and fall, most often in August.
How often is Mason Lake stocked?
Mason Lake is stocked intermittently — 13 recorded stockings between 1995 and 2023.
How many fish have been stocked in Mason Lake?
About 8,833 fish have been stocked in Mason Lake across 13 recorded events since 1995, per Washington fish & wildlife agency.
Do you need a fishing license to fish Mason Lake?
Yes, all anglers age 16 and older generally need a valid Washington freshwater fishing license. Always review current regulations from Washington fish & wildlife agency for site-specific rules, bag limits, or stamps.
How do you catch stocked trout in Mason Lake?
Freshly stocked trout in Mason Lake typically respond well to floating dough bait (such as PowerBait) floated 12–18 inches off bottom on light 4–6 lb leader, live nightcrawlers under a bobber, and small inline spinners or spoons retrieved along shorelines and drop-offs.