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

Media mentions

Business Insider: The Winners and Losers of the New H-1B Era

Partner Catherine Macris discusses how evolving H-1B policies are shaping employers’ ability to recruit foreign talent, particularly in highly specialized fields.

Learn more

Awards

Fragomen Professionals and Employee Network Shortlisted for 2027 TLC Lions Human Awards Europe

Two Fragomen professionals and our BeYou@Fragomen employee network have been shortlisted for the 2027 TLC Lions Human Awards Europe, recognising their contributions to inclusive leadership and a people-centred workplace culture.

Learn more

Awards

Fragomen’s Worldwide Immigration Trends Report 2026 Wins at the FEM EMEA EMMAs

Fragomen is honored with the 2026 FEM EMEA EMMA in the "Thought Leadership - Best Survey or Research Study of the Year" category for its 2026 Worldwide Immigration Trends Report. 

Learn more

Media mentions

Law360: How A New Case Redefines The Birthright Citizenship Battle

Partner Daniel Pierce and Senior Associate Daniel D. Schaeffer examine US birthright citizenship challenges and the implications of recent court rulings for nationwide relief in immigration litigation.

Learn more

Video

What Is ESTA? Five Common Mistakes to Avoid When Traveling to the US

Los Angeles Partner Emily Allen explains what ESTA is, who may be eligible under the US Visa Waiver Program and five common mistakes travelers should avoid when visiting the United States for business or tourism.

Learn more
Generic Insights

Fragomen news

Case Study: Securing a Positive Outcome in a Complex Adult Dependent Relative Appeal

Fragomen supported an Adult Dependent Relative applicant through a complex appeal, using coordinated medical and social care evidence to demonstrate his holistic care needs before the Home Office withdrew its refusal and indicated that the application would be granted.

Learn more

Blog post

Moving Talent, Moving Families: Navigating Family Reunification in Europe

Senior Manager Andreia Ghimis and Senior Immigration Consultant Louise Farren explore how family reunification rules across Europe can affect international moves and why employers should assess family eligibility, immigration requirements and likely timelines alongside an employee’s work authorization.

Learn more

Media mentions

Business Insider: How Would the $70,000 Fee on International Students Working in the US Impact Schools and Grads? 2 Lawyers Break It Down.

Partner Aaron Blumberg discusses how a proposed $70,000 fee for international students seeking US work authorization could affect students, universities and employers.

Learn more

Blog post

How to Qualify for Permanent Residence and Polish Citizenship

Poland Immigration Strategy Director Tomasz Rogala and Senior Associate Tomasz Rdzanek outline the principal pathways to permanent residence and Polish citizenship, including key residence, language and income considerations and potential future reforms.

Learn more

Fragomen news

Comment on USCIS Mandatory Electronic Filing RuleLearn more

Fragomen news

Fragomen Collaboration Selected as 2026 European Labour Authority Good Practice

Fragomen, together with SICPA and Deutsche Rentenversicherung Bund, has been selected by the European Labour Authority as a 2026 Good Practice for an EU-funded WE BUILD use case exploring how digital identity solutions could help transform PD A1 processes and support cross-border labour mobility in Europe.

Learn more

Media mentions

The Caterer: Right to Work Scheme: Have You Carried Out Checks on Temporary Staff?

Senior Manager Louise Senior highlights how expanded UK right to work requirements will affect hospitality businesses using temporary and contingent workers.

Learn more

Media mentions

Business Insider: The Winners and Losers of the New H-1B Era

Partner Catherine Macris discusses how evolving H-1B policies are shaping employers’ ability to recruit foreign talent, particularly in highly specialized fields.

Learn more

Awards

Fragomen Professionals and Employee Network Shortlisted for 2027 TLC Lions Human Awards Europe

Two Fragomen professionals and our BeYou@Fragomen employee network have been shortlisted for the 2027 TLC Lions Human Awards Europe, recognising their contributions to inclusive leadership and a people-centred workplace culture.

Learn more

Awards

Fragomen’s Worldwide Immigration Trends Report 2026 Wins at the FEM EMEA EMMAs

Fragomen is honored with the 2026 FEM EMEA EMMA in the "Thought Leadership - Best Survey or Research Study of the Year" category for its 2026 Worldwide Immigration Trends Report. 

Learn more

Media mentions

Law360: How A New Case Redefines The Birthright Citizenship Battle

Partner Daniel Pierce and Senior Associate Daniel D. Schaeffer examine US birthright citizenship challenges and the implications of recent court rulings for nationwide relief in immigration litigation.

Learn more

Video

What Is ESTA? Five Common Mistakes to Avoid When Traveling to the US

Los Angeles Partner Emily Allen explains what ESTA is, who may be eligible under the US Visa Waiver Program and five common mistakes travelers should avoid when visiting the United States for business or tourism.

Learn more
Generic Insights

Fragomen news

Case Study: Securing a Positive Outcome in a Complex Adult Dependent Relative Appeal

Fragomen supported an Adult Dependent Relative applicant through a complex appeal, using coordinated medical and social care evidence to demonstrate his holistic care needs before the Home Office withdrew its refusal and indicated that the application would be granted.

Learn more

Blog post

Moving Talent, Moving Families: Navigating Family Reunification in Europe

Senior Manager Andreia Ghimis and Senior Immigration Consultant Louise Farren explore how family reunification rules across Europe can affect international moves and why employers should assess family eligibility, immigration requirements and likely timelines alongside an employee’s work authorization.

Learn more

Media mentions

Business Insider: How Would the $70,000 Fee on International Students Working in the US Impact Schools and Grads? 2 Lawyers Break It Down.

Partner Aaron Blumberg discusses how a proposed $70,000 fee for international students seeking US work authorization could affect students, universities and employers.

Learn more

Blog post

How to Qualify for Permanent Residence and Polish Citizenship

Poland Immigration Strategy Director Tomasz Rogala and Senior Associate Tomasz Rdzanek outline the principal pathways to permanent residence and Polish citizenship, including key residence, language and income considerations and potential future reforms.

Learn more

Fragomen news

Comment on USCIS Mandatory Electronic Filing RuleLearn more

Fragomen news

Fragomen Collaboration Selected as 2026 European Labour Authority Good Practice

Fragomen, together with SICPA and Deutsche Rentenversicherung Bund, has been selected by the European Labour Authority as a 2026 Good Practice for an EU-funded WE BUILD use case exploring how digital identity solutions could help transform PD A1 processes and support cross-border labour mobility in Europe.

Learn more

Media mentions

The Caterer: Right to Work Scheme: Have You Carried Out Checks on Temporary Staff?

Senior Manager Louise Senior highlights how expanded UK right to work requirements will affect hospitality businesses using temporary and contingent workers.

Learn more
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Important Updates
Important Updates
October 16, 2026 | IndiaIndia: Minimum Salary Level for Employment Visas Significantly Increased
October 16, 2026 | United StatesBusiness Insider: The Winners and Losers of the New H-1B Era
October 16, 2026 | CanadaCanada: Express Entry Changes to Prioritize High-Wage Occupations
October 16, 2026 | European UnionEuropean Union/Schengen Area: Internal Schengen Border Checks Situation
October 16, 2026 | United Kingdom, IrelandFragomen Professionals and Employee Network Shortlisted for 2027 TLC Lions Human Awards Europe
October 16, 2026 | IndiaIndia: Minimum Salary Level for Employment Visas Significantly Increased
October 16, 2026 | United StatesBusiness Insider: The Winners and Losers of the New H-1B Era
October 16, 2026 | CanadaCanada: Express Entry Changes to Prioritize High-Wage Occupations
October 16, 2026 | European UnionEuropean Union/Schengen Area: Internal Schengen Border Checks Situation
October 16, 2026 | United Kingdom, IrelandFragomen Professionals and Employee Network Shortlisted for 2027 TLC Lions Human Awards Europe
October 16, 2026 | IndiaIndia: Minimum Salary Level for Employment Visas Significantly Increased
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