Castle Island Ventures is a venture capital firm focused exclusively on public blockchains, investing in early-stage infrastructure and application companies at the intersection of traditional finance and crypto. It was founded in 2018 by former Fidelity executives Nic Carter and Matt Walsh.
34% of their portfolio is in Crypto & Web3. Average disclosed round size is $27.3M (across 69 rounds with reported amounts).
Portfolio
57
Fund Size
$250M
Top Stage
Seed
Last 12 Mo
4
Team
Portfolio Breakdown
Stage Distribution
Sector Distribution
Investment Activity
DealsAvg Round Size
Portfolio
76 investments
| Company | Round | Amount | Date |
|---|---|---|---|
 Félix | Series C | $200M | Sep 2026 |
 Cyclops | Series A | $20M | Jul 2026 |
 Project Eleven | Series A | $20M | Jan 2026 |
 Valinor | Series A | $54M | Jan 2026 |
| Cyclops | Series A | $20M | Jan 2026 |
 Talos | Series B | $45M | Jan 2026 |
 Tesser | Seed | $4.5M | Oct 2025 |
 BOB | Strategic | — | Aug 2025 |
 Surus | Seed | $8M | Feb 2025 |
 Nirvana Labs | Seed | $6M | Jan 2025 |
 TYB | Series A | $11M | Jan 2025 |
| Félix | Series B | $75M | Jan 2025 |
| PPear Protocol | Unknown | $4.1M | Jan 2025 |
 OpenFX | Seed | $23M | Jan 2025 |
| Project Eleven | Seed | $6M | Jan 2025 |
 Hata | Seed | $4.2M | Oct 2024 |
 Yellow Card | Series C | $33M | Oct 2024 |
 Arch | Seed | $5M | Aug 2024 |
| FFélix Pago | Series C | $87M | May 2024 |
| BOB | Unknown | — | Apr 2024 |
| FFélix Pago | Series A | $15.5M | Jan 2024 |
| AAndrena (DAWN) | Series A | $18M | Jan 2024 |
| DDAWN (Andrena) | Series A | $18M | Jan 2024 |
 Dust Identity | Series B | $40M | Dec 2023 |
 CAT Labs | Pre-Seed | $4.3M | Apr 2023 |
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Top Co-Investors
Coinbase Ventures13 shared
Illuminate Financial8 shared
Fidelity Investments8 shared
CMT Digital8 shared
Andreessen Horowitz8 shared
Digital Currency Group7 shared
Initialized Capital7 shared
Avon Ventures7 shared
General Catalyst6 shared
PayPal Ventures5 shared
Dragonfly5 shared
Polychain Capital5 shared
Jump Capital5 shared
Notation Capital5 shared
DRW Venture Capital4 shared
Galaxy Ventures4 shared
Blockchange Ventures4 shared
Contour Venture Partners4 shared
F-Prime Capital4 shared
Wintermute Ventures4 shared
Last updated: 7 October 2026