William Diaz

Senior Manager

William Diaz

William Diaz
William Diaz
  • People

Senior Manager

William Diaz

Country / Territory

  • United KingdomUnited Kingdom

Get in touch

Languages

  • English

Contact information

Email

[email protected]

T:+44 (0)207 090 9272

F:+44 (0)207 090 9101

London

Fragomen LLP

1st Floor, 95 Gresham St,

London EC2V 7NA

United Kingdom

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Get in touch

Languages

  • English

Contact information

Email

[email protected]

T:+44 (0)207 090 9272

F:+44 (0)207 090 9101

London

Fragomen LLP

1st Floor, 95 Gresham St,

London EC2V 7NA

United Kingdom

Connect via Linkedin

Get in touch

Languages

  • English

Contact information

Email

[email protected]

T:+44 (0)207 090 9272

F:+44 (0)207 090 9101

London

Fragomen LLP

1st Floor, 95 Gresham St,

London EC2V 7NA

United Kingdom

Connect via Linkedin
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William is a Senior Manager based in Fragomen’s London office. He assists clients in a variety of industries including finance, technology and entertainment, with a particular emphasis on assisting with complex consular filing for treaty investors, intracompany transferees and individuals of extraordinary ability.

William frequently advises small and medium-sized enterprises throughout the EMEA region in expanding to the U.S. and transferring key personnel. These clients range from start-ups to long established businesses across a range of professions. 

He has previously volunteered with various organisations, including a civil liberties non-profit and an international criminal tribunal. 

Education

  • Leiden University, LL.M., 2011
  • Pace University School of Law, J.D., 2009
  • Fordham University, B.A., 2005

More from William

Admissions

Immigration Credentials: Registered Attorney with the United States Department of Justice’s Executive Office for Immigration Review, 2013-present

Bar Admissions: New York State

Professional accomplishments

Member, American Immigration Lawyers Association (AILA)

Former Member, AILA CBP Liaison Committee

Experience

Obtained a nonimmigrant waiver of inadmissibility for a noted entertainer with previous criminal convictions.

Advised a multinational vehicle manufacturer in transferring key managerial and technical personnel for the expansion of their U.S. operations.

Helped a search engine provider with a complex business ownership structure acquire E-2 company registration and transfer key managers and executives to the United States.

Devised strategies to ensure a television production company could transfer key talent on an expedited basis during a period of prolonged global disruption in U.S. visa issuance.

Advised a start-up technology marketing firm and guided U.S. expansion strategy to support treaty investor visas for key managerial and specialist personnel.

Publications and lectures

Author, “Leading Britain’s Conversation: One Old Arrest Can Stop You Entering the USA, Even If You Were Never Convicted.” Fragomen, 16 March 2026.

Author, “Tightening immigration rules will impact the games industry in 2026.” Games Industry, 6 February 2026.

Author, “Games Industry: US H-1B Visas: Alternatives to a $100,000 Fee.” Fragomen, 29 October 2025.

Author, “Tech and Global Mobility: The impact of the new US Administration.” Computer Weekly, 4 March 2025.

Panelist, “Bobbing for Visas: Alternative Uses for the B Visa Category.” AILA Rome District Chapter Fall Conference 2023, London, UK, October 2023.

Presenter, “US Growth Programme: Visas for investment and expansion.” TechNation US Growth Workshop 3.0, London, UK, September 2022.

Panelist, “Ch-Ch-Changes: Regulatory, Policy, and Adjudications.” AILA National Conference 2020, Webinar, July 2020.

Presenter, “US Visas for Irish Investors.” Dublin Chamber of Commerce, Dublin, Ireland, February 2020.

Presenter, “Obtaining the Right Visas.” UK Department of International Trade, Cambridge, UK, October 2019.

Presenter, “Visa for US expansion.” Fingal Dublin Chamber, Dublin, Ireland, February 2019.

Presenter, “US Immigration for Investors.” South West World Trade Summit, Bristol, UK, July 2018.

Presenter, “US Immigration for Latvian Investors.” Gateway to the USA Program, Riga, Latvia, May 2018.

Panelist, “Humanitarian Options of Last Resort.” AILA National Conference 2017, New Orleans, Louisiana, June 2017.

Co-author, “Humanitarian Options of Last Resort.” AILA Immigration Practice Pointers (2017-18 Ed.), Pages 575-585, 2017.

Panelist, “Advanced E Visas.” AILA Rome District Chapter Fall Conference 2016, Amsterdam, Netherlands, October 2016.

Author, “Common US immigration consequences of mergers and acquisitions.” Human Resource Management International Digest, Volume 23, Issue 7 (2015). Print and web.

Author, “Want to work in the US? The secret to securing a successful application.” The Stage, September 25, 2015. Web.

Author, “Global Mobility Strategies for SMEs Expanding to the US.” Corporate Vision Magazine, August 2015: 42-43. Print and web.

Author, “From Posting to Permanent Residency.” Global: The International Briefing, December 2015: 40-41. Print and web.

Author, “Transferring Professional Athletes to the U.S.” HRreview, July 10, 2015. Web.

Author, “US visa eligibility: five HR issues when transferring employees.” Personnel Today, August 28, 2015. Web.

Panelist, "Legal IT Roundtable." Roundtable event, The Law Society Gazette, London, UK, July 2015.

Presenter, “US immigration for start-ups.” Presentation, Access to the US and the US Ignite Program, London, UK, June 2015.

Contributor, “Clarkson faced police interview over attack.” The Times, 27 March 2015.

Presenter, “US immigration overview.” Presentation, Techstars, London, UK, January 2015.

Author, “Dualist, but not Divergent: Evaluating United States Implementation of the 1267 Sanctions Regime.” Liberty University Law Review, Volume 5, Issue 3 (2011): 333-378. Print and web.

William’s insights

March 16, 2026 | Media mentions

Leading Britain's Conversation: One Old Arrest Can Stop You Entering the USA, Even If You Were Never ConvictedRead more

February 9, 2026 | Media mentions

Games Industry: Tightening Immigration Rules Will Impact the Games Industry in 2026Read more

October 29, 2025 | Media mentions

Games Industry: US H-1B Visas: Alternatives to a $100,000 FeeRead more
More related insights

William’s insights

March 16, 2026 | Media mentions

Leading Britain's Conversation: One Old Arrest Can Stop You Entering the USA, Even If You Were Never ConvictedRead more

February 9, 2026 | Media mentions

Games Industry: Tightening Immigration Rules Will Impact the Games Industry in 2026Read more

October 29, 2025 | Media mentions

Games Industry: US H-1B Visas: Alternatives to a $100,000 FeeRead more
More related insights

William’s insights

March 16, 2026 | Media mentions

Leading Britain's Conversation: One Old Arrest Can Stop You Entering the USA, Even If You Were Never ConvictedRead more

February 9, 2026 | Media mentions

Games Industry: Tightening Immigration Rules Will Impact the Games Industry in 2026Read more

October 29, 2025 | Media mentions

Games Industry: US H-1B Visas: Alternatives to a $100,000 FeeRead more
More related insights

Country / Territory

  • United KingdomUnited Kingdom

Get in touch

Languages

  • English

Contact information

Email

[email protected]

T:+44 (0)207 090 9272

F:+44 (0)207 090 9101

London

Fragomen LLP

1st Floor, 95 Gresham St,

London EC2V 7NA

United Kingdom

Connect via Linkedin

William’s insights

March 16, 2026 | Media mentions

Leading Britain's Conversation: One Old Arrest Can Stop You Entering the USA, Even If You Were Never ConvictedRead more

February 9, 2026 | Media mentions

Games Industry: Tightening Immigration Rules Will Impact the Games Industry in 2026Read more

October 29, 2025 | Media mentions

Games Industry: US H-1B Visas: Alternatives to a $100,000 FeeRead more
More related insights

Share

  • Twitter
  • Facebook
  • LinkedIn

Share

  • Twitter
  • Facebook
  • LinkedIn

Get in touch

Languages

  • English

Contact information

Email

[email protected]

T:+44 (0)207 090 9272

F:+44 (0)207 090 9101

London

Fragomen LLP

1st Floor, 95 Gresham St,

London EC2V 7NA

United Kingdom

Connect via Linkedin

William’s insights

March 16, 2026 | Media mentions

Leading Britain's Conversation: One Old Arrest Can Stop You Entering the USA, Even If You Were Never ConvictedRead more

February 9, 2026 | Media mentions

Games Industry: Tightening Immigration Rules Will Impact the Games Industry in 2026Read more

October 29, 2025 | Media mentions

Games Industry: US H-1B Visas: Alternatives to a $100,000 FeeRead more
More related insights

Share

  • Twitter
  • Facebook
  • LinkedIn

Share

  • Twitter
  • Facebook
  • LinkedIn

Get in touch

Languages

  • English

Contact information

Email

[email protected]

T:+44 (0)207 090 9272

F:+44 (0)207 090 9101

London

Fragomen LLP

1st Floor, 95 Gresham St,

London EC2V 7NA

United Kingdom

Connect via Linkedin

William’s insights

March 16, 2026 | Media mentions

Leading Britain's Conversation: One Old Arrest Can Stop You Entering the USA, Even If You Were Never ConvictedRead more

February 9, 2026 | Media mentions

Games Industry: Tightening Immigration Rules Will Impact the Games Industry in 2026Read more

October 29, 2025 | Media mentions

Games Industry: US H-1B Visas: Alternatives to a $100,000 FeeRead more
More related insights

Share

  • Twitter
  • Facebook
  • LinkedIn

Share

  • Twitter
  • Facebook
  • LinkedIn

Explore more at Fragomen

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A More Purposeful UK Immigration System: What Expanded Access to the Global Talent Visa Means for UK Immigration Policy

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Learn more

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Polish Citizenship by Descent: Do You Qualify?

Poland Immigration Strategy Director Tomasz Rogala and Senior Associate Tomasz Rdzanek discuss how Polish citizenship by descent works, who may qualify, the documentation typically required and common eligibility challenges.

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Times of India: Trump Admin Restores USCIS Power to Deny Immigration Requests Outright Without Seeking More Proof

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Fragomen Retains Band 1 Ranking & Receives Four Individual Rankings in Chambers High Net Worth 2026 Guide

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Partner Louise Haycock discussed the Migration Advisory Committee’s Temporary Shortage List recommendations and the need for clear workforce plans and transitional arrangements.

Learn more

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A More Purposeful UK Immigration System: What Expanded Access to the Global Talent Visa Means for UK Immigration Policy

In our latest blog, UK Government Affairs Strategy Lead @Shuyeb Muquit examines the expanded access to the Global Talent visa and what it signals about the direction of UK immigration policy

Learn more

Video

Polish Citizenship by Descent: Do You Qualify?

Poland Immigration Strategy Director Tomasz Rogala and Senior Associate Tomasz Rdzanek discuss how Polish citizenship by descent works, who may qualify, the documentation typically required and common eligibility challenges.

Learn more

Media mentions

Times of India: Trump Admin Restores USCIS Power to Deny Immigration Requests Outright Without Seeking More Proof

Senior Counsel Mitch Wexler discusses USCIS’ restored authority to deny certain immigration benefit requests without first issuing a Request for Evidence and the importance of complete initial filings.

Learn more

Fragomen news

Comment on DHS Proposed Rule on Discretionary Employment AuthorizationLearn more

Blog post

How the Middle East Is Building Workforce Mobility Resilience Amid Regional Disruption

Partner Shayan Sultan discusses how geopolitical disruption, intensifying talent competition and digital transformation are reshaping workforce mobility and compliance across the Middle East.

Learn more

Awards

Partner Karolina Schiffter Recognised in Lexology Index: Thought Leaders Global Elite 2027

Partner Karolina Schiffter is recognised in the Lexology Index: Thought Leaders Global Elite 2027 report.

Learn more

Blog post

Canada’s Immigration Dual Reality: Narrower Access, Persistent Demand

Partner Jack Kim discusses how Canada’s increasingly selective and complex immigration system is affecting talent access, retention and long-term workforce planning for employers.

Learn more

Blog post

UK Temporary Shortage List Review: What the Migration Advisory Committee's Recommendations Mean for Employers

UK Government Affairs Strategy Director Shuyeb Muquit explores what the recommendations mean, what’s still uncertain and what employers should be watching next

Learn more

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A1-Bescheinigung für Geschäftsreisen und Entsendungen: Was Arbeitgeber wissen müssen

In this blog, Senior Manager Katharina Vorländer explains when employers need an A1 certificate for employees traveling or working temporarily within Europe, the application process and how timely planning can help manage social security compliance risks.

Learn more

Awards

Fragomen Retains Band 1 Ranking & Receives Four Individual Rankings in Chambers High Net Worth 2026 Guide

Fragomen and UK team members are ranked in the “Immigration: High Net Worth Individuals – UK-wide” category of the Chambers High Net Worth 2026 Guide.

Learn more

Blog post

Establishing a Business Presence in Switzerland: Key Considerations for Employers

In this blog, Director Ana Bessa Santos explores what Swiss authorities expect from employers when assessing work permit applications—including why a well-developed business plan, realistic growth projections and evidence of a genuine operational presence are critical to supporting both initial applications and future permit renewals.

Learn more

Media mentions

Personnel Today: Migration Committee Proposes to Cut 24 Occupations From New Shortage List

Partner Louise Haycock discussed the Migration Advisory Committee’s Temporary Shortage List recommendations and the need for clear workforce plans and transitional arrangements.

Learn more
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August 7, 2026 | United StatesUnited States: USCIS Announces Termination of TPS For Burma and South Sudan, with TPS Work Authorization No Longer Valid
August 7, 2026 | CanadaCanada: Open Work Permit Eligibility for Manitoba Prospective Provincial Nominees Introduced
August 7, 2026 | MalaysiaMalaysia: Salary Threshold for Labour Market Test Exemption Increased
August 7, 2026 | United StatesUnited States: DHS Expands 9-11 Response Fee to H-1B and L-1 Extensions
August 7, 2026 | United StatesUnited States: DHS to Propose Elimination of 60-Day Nonimmigrant Grace Period
August 7, 2026 | United StatesUnited States: USCIS Announces Termination of TPS For Burma and South Sudan, with TPS Work Authorization No Longer Valid
August 7, 2026 | CanadaCanada: Open Work Permit Eligibility for Manitoba Prospective Provincial Nominees Introduced
August 7, 2026 | MalaysiaMalaysia: Salary Threshold for Labour Market Test Exemption Increased
August 7, 2026 | United StatesUnited States: DHS Expands 9-11 Response Fee to H-1B and L-1 Extensions
August 7, 2026 | United StatesUnited States: DHS to Propose Elimination of 60-Day Nonimmigrant Grace Period
August 7, 2026 | United StatesUnited States: USCIS Announces Termination of TPS For Burma and South Sudan, with TPS Work Authorization No Longer Valid
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